Which one of the following is not an inter services establishment of the Indian Armed Forces, that is, not a joint institution serving all three services together?

Introduction / Context:
This question checks your understanding of major training and educational institutions associated with the Indian Armed Forces. Some institutions are inter services or tri service establishments, which means they serve the Army, Navy, and Air Force together. Others are specific to a single service. Identifying which institution is not inter services helps you distinguish between joint training academies and service specific academies.

Given Data / Assumptions:

The options list Officers Training Academy, National Defence Academy, National Defence College, and Armed Forces Medical College.
An inter services establishment is one that is designed to cater to officers or personnel from all three services of the Armed Forces.
We must pick the option that does not operate as a tri service or joint institution in this sense.

Concept / Approach:
The National Defence Academy is a well known tri service academy where cadets of the Army, Navy, and Air Force train together before going on to their respective specialised academies. The National Defence College also provides higher level training and courses for senior officers from all three services and sometimes participants from civil services and friendly foreign countries. The Armed Forces Medical College trains medical officers and personnel for all the three services, making it an inter services medical institution. In contrast, the Officers Training Academy primarily serves the Army by training officers for the Indian Army, and is not a tri service establishment.

Step-by-Step Solution:
Step 1: Identify the nature of the National Defence Academy. It is the joint services academy where cadets from the Army, Navy, and Air Force undergo common training, which makes it clearly inter services.Step 2: Identify the National Defence College as a senior level institution that conducts courses for officers from all three services and civil services, thus also functioning as an inter services establishment.Step 3: Recognise that the Armed Forces Medical College is run for the benefit of the entire Armed Forces, providing medical training and education to personnel from all three services, which again makes it inter services.Step 4: Note that the Officers Training Academy mainly commissions officers into the Indian Army, especially through short service commission courses, and does not function as a tri service training academy. Therefore it is the institution that is not inter services.

Verification / Alternative check:
If you look at the official descriptions of these institutions, National Defence Academy, National Defence College, and Armed Forces Medical College are all explicitly described as joint or inter services institutions with officers and cadets from multiple services training together. On the other hand, the Officers Training Academy is listed under Army specific training establishments and is primarily associated with commissioning officers for the Army. This difference in mandate and composition confirms that Officers Training Academy is the correct answer to the question.

Why Other Options Are Wrong:
National Defence Academy is clearly inter services as it trains cadets from the Army, Navy, and Air Force together during their initial officer training, so this option is not correct for the question.

National Defence College conducts courses in national security and strategic studies for senior officers from all three services and senior civil servants, so it is a prominent inter services establishment and not the correct answer here.
Armed Forces Medical College is a tri service medical institution that prepares doctors and medical staff for the Army, Navy, and Air Force, making it an inter services organisation and not the one the question is asking for.

Common Pitfalls:
A common mistake is to assume that any institution with the words Armed Forces in its name must be inter services, while anything with Army, Navy, or Air Force alone must be single service. Although this works in many cases, it is better to understand the mandate of each institution. Another pitfall is to confuse the Officers Training Academy with the National Defence Academy because both are involved in officer training. Remember that National Defence Academy is the joint academy for all three services at the pre commission stage, while the Officers Training Academy is primarily for Army officers, especially through short service commissions. This distinction helps answer the question correctly.

Final Answer:
The Officers Training Academy is not an inter services establishment, whereas the other listed institutions are joint or tri service establishments.