C25, India first indigenously developed high thrust cryogenic rocket engine, was successfully ground tested by ISRO for use in which launch vehicle?

Introduction / Context:
Space technology questions often focus on India advances in launch vehicle development. Cryogenic engines are crucial for lifting heavy payloads into higher orbits. The C25 engine is a significant achievement for the Indian Space Research Organisation because it is a high thrust cryogenic engine developed within the country. This question asks you to recall for which launch vehicle this engine was designed.

Given Data / Assumptions:

- The engine in question is C25, a high thrust cryogenic rocket engine.

- It is indigenously developed and successfully ground tested by ISRO.

- The options list different versions of the Geosynchronous Satellite Launch Vehicle: GSLV Mark II, GSLV Mark III, GSLV Mark IV and GSLV Mark V.

- We must identify the specific launch vehicle that uses the C25 stage.

Concept / Approach:
GSLV Mark III is India heavy lift launch vehicle designed to place heavier communication satellites into geosynchronous transfer orbit. For this, it requires a powerful cryogenic upper stage. The C25 engine powers the cryogenic upper stage of GSLV Mark III. Earlier versions like GSLV Mark II used a different cryogenic stage, and the names GSLV Mark IV and Mark V in the options are distractors rather than officially operational vehicles. Therefore, recognising the connection between heavy lift and C25 helps you arrive at GSLV Mark III.

Step-by-Step Solution:
Step 1: Recall that C25 is a cryogenic engine associated with a heavy lift configuration. Step 2: Identify that among the given options, GSLV Mark III is known as India heavy lift launch vehicle. Step 3: Remember that ISRO announcements often mentioned the C25 cryogenic stage in relation to GSLV Mark III test flights. Step 4: Understand that GSLV Mark II has a smaller cryogenic stage and that Mark IV and Mark V are not the standard designations widely used in official launches. Step 5: Select GSLV Mark III as the correct answer.

Verification / Alternative check:
You can verify by recalling specific mission names such as GSLV Mark III D1, which carried the GSAT series satellites and later supported missions related to crew module tests. News reports describing these missions clearly mention the C25 cryogenic upper stage as part of GSLV Mark III. Cross checking with basic ISRO mission summaries confirms this linkage.

Why Other Options Are Wrong:

Option A (GSLV Mark II) uses a cryogenic upper stage but not the C25 high thrust version designed for heavy lift capability.

Option C (GSLV Mark IV) is not the officially used designation for any major operational ISRO launch vehicle and appears here as a distractor.

Option D (GSLV Mark V) similarly does not match the naming of the vehicle that actually uses the C25 stage.

Common Pitfalls:
A common error is to assume that all GSLV variants use the same cryogenic engine or to get confused by the similar sounding names. To avoid this, remember a simple association: C25 belongs with GSLV Mark III, the heavy lift vehicle, while earlier Mark II versions use different cryogenic configurations. Making a small table of vehicle names, payload capacities and key engine types can greatly reduce confusion.

Final Answer:
The correct answer is GSLV Mark III, which uses the C25 indigenously developed high thrust cryogenic engine as its upper stage.