In August 2016, highly sensitive technical information related to an Indian defence platform was reported to have been leaked. This leak primarily concerned which one of the following defence platforms of India?

Introduction / Context:
Defence and national security related current affairs are a frequent source of questions in competitive examinations. In 2016, there was a major news story about the leak of highly sensitive technical documents concerning a key Indian defence platform. This incident involved detailed technical specifications and was considered a serious security concern. The question asks you to identify which category of defence platform was involved in that leak.

Given Data / Assumptions:
- The leak occurred around August 2016 and involved sensitive technical information.
- The options given are fifth generation fighter aircraft, combat helicopters, submarines and unmanned aerial vehicles.
- The question expects awareness of a specific reported incident, not general knowledge of defence technologies.
- It is assumed that the student has followed important defence related news events from that period.

Concept / Approach:
In 2016, media reports highlighted a leak of thousands of pages of sensitive technical documents related to the Scorpene class submarines being built for the Indian Navy. These documents allegedly contained detailed data about the submarines' capabilities and systems. This created concern about the security of underwater warfare assets and the confidentiality of defence contracts. The approach to this question is therefore to recall this widely reported incident and match it with the correct category of platform from the options provided.

Step-by-Step Solution:
Step 1: Recall that in August 2016 there was widespread media coverage about a data leak concerning submarine specifications associated with the Scorpene project. Step 2: The leaked documents reportedly included technical details about stealth capabilities, weapon systems and communication parameters of submarines under construction. Step 3: No similarly prominent leak at that time was reported about fifth generation fighter aircraft, combat helicopters or unmanned aerial vehicles of India. Step 4: Therefore, the defence platform linked to the sensitive information leak was the submarine platform. Step 5: Among the options, the category that corresponds to this is submarines, making that the correct choice.

Verification / Alternative check:
Cross checking with standard current affairs compilations for 2016 or archived news sources for that year confirms that the major leak story concerned the Scorpene class submarines being built with foreign collaboration for the Indian Navy. These sources emphasise that the leaked documents contained detailed information about submarine performance and systems, not about fighters, helicopters or unmanned aerial vehicles. The absence of equally significant reports in that period about leaks related to other platforms further supports the identification of submarines as the correct answer.

Why Other Options Are Wrong:
Option A (Fifth generation fighter aircraft) is wrong because there was no major news in August 2016 about a comparable leak of sensitive technical documents concerning fifth generation fighters in the Indian context.
Option B (Combat helicopters) is wrong because, while India did acquire and upgrade combat helicopters, the specific data leak story in 2016 did not focus on helicopter platforms.
Option D (Unmanned aerial vehicles) is wrong because, although unmanned systems are increasingly important in defence, the 2016 leak story was about submarine capabilities and did not centre on unmanned aerial vehicles.

Common Pitfalls:
A common pitfall is to guess based on the perceived sensitivity or glamour of certain platforms, such as fifth generation fighters or unmanned aerial vehicles, instead of recalling the exact news event. Another mistake is to conflate different defence controversies, such as procurement disputes or cost issues, with specific security breaches like document leaks. To avoid such errors, candidates should maintain a clear timeline of major defence events in recent years, noting which platform each event concerned.

Final Answer:
The sensitive information leaked in August 2016 primarily concerned submarines, specifically the Scorpene class submarines being built for the Indian Navy.