In Indian space technology, which of the following is recognised as India's heaviest communication satellite built by ISRO?

Introduction / Context:
India's space agency, the Indian Space Research Organisation (ISRO), has launched many communication satellites under the GSAT series. General knowledge and competitive exams often ask about record-holding missions, such as the heaviest satellite built by ISRO so far. Knowing these facts helps candidates follow India's technological progress and answer space-science questions accurately.

Given Data / Assumptions:

We are given:
- Several GSAT satellites listed as options.
- The question clearly refers to the heaviest communication satellite built by ISRO.
- We assume the comparison is within ISRO-built communication satellites, not foreign-built payloads.

Concept / Approach:
The approach is simple factual recall. ISRO's GSAT series provides communication services like television, telephony, and broadband. Among these, GSAT - 11 is widely known as the heaviest satellite built by ISRO, weighing over 5 tonnes at launch. The task is to identify this specific satellite from the list of options.

Step-by-Step Solution:
Step 1: Recall that GSAT satellites are Indian communication satellites developed by ISRO.
Step 2: Remember that GSAT - 11 was described by ISRO as its heaviest communication satellite at the time of launch.
Step 3: Compare the listed satellites: GSAT - 09, GSAT - 10, GSAT - 11, GSAT - 13, and INSAT - 4A.
Step 4: Identify GSAT - 11 as the correct option because it is specifically known for its record mass and high-throughput capability.
Step 5: Confirm that none of the other satellites in the list exceeded GSAT - 11 in launch mass at that time.

Verification / Alternative check:
You can verify this fact by checking official ISRO mission brochures or press releases. They clearly mention GSAT - 11 as the heaviest communication satellite built by ISRO, designed to significantly improve broadband and communication coverage over India and nearby regions.

Why Other Options Are Wrong:
- GSAT - 09: This is the South Asia Satellite, lighter and with a different regional cooperation focus.
- GSAT - 13: A communication satellite, but not the heaviest one built by ISRO.
- GSAT - 10: Important for communication services, yet again lighter than GSAT - 11.
- INSAT - 4A: Part of the older INSAT series, smaller and not comparable in mass to GSAT - 11.

Common Pitfalls:
Candidates may confuse 'most recent' with 'heaviest' or assume that any higher-numbered satellite like GSAT - 13 must be bigger. Another common mistake is mixing the INSAT and GSAT series. Always focus on the specific property being asked about—in this case, the heaviest communication satellite built by ISRO, which is GSAT - 11.

Final Answer:
Correct option: GSAT - 11