The Indian Space Research Organisation (ISRO) successfully launched a heavy communication satellite on board which launch vehicle, marking an important milestone for the Indian space programme?

Introduction / Context:
The Indian Space Research Organisation (ISRO) has developed a family of launch vehicles to place satellites into orbit. One of the major milestones in India's space programme was the successful launch of a heavy communication satellite using the country's heaviest rocket. This question asks which launch vehicle was used for that significant mission, highlighting awareness of India's advancement in space technology.

Given Data / Assumptions:
- The question refers to a heavy communication satellite launched by ISRO.
- The focus is on the type of launch vehicle used.
- Options given are various versions of the Geosynchronous Satellite Launch Vehicle (GSLV): Mk III, Mk II, Mk I, plus a none of the above option.
- Only one of these correctly describes the heaviest and most advanced GSLV variant used for such a landmark mission.

Concept / Approach:
GSLV Mk III is ISRO's heavy lift launch vehicle designed to place heavier communication satellites into geostationary transfer orbit and also to support crewed missions in the future. Earlier versions, GSLV Mk I and Mk II, carried lighter loads and represented earlier stages of development. When ISRO launched a very heavy communication satellite and highlighted the achievement globally, it was on board the GSLV Mk III. Therefore, knowledge of the relative capabilities of these rocket variants leads to the correct answer.

Step-by-Step Solution:
Step 1: Recognise that the question emphasises a heavy communication satellite and an important milestone for the Indian space programme. Step 2: Recall that GSLV Mk III is the most powerful rocket developed by ISRO, sometimes called a heavy lift vehicle. Step 3: Identify that GSLV Mk I and Mk II are earlier versions with lower payload capacities, used before Mk III became operational. Step 4: Understand that a notable landmark launch using a heavy vehicle must logically refer to GSLV Mk III. Step 5: Select GSLV Mk III as the correct launch vehicle for this mission.

Verification / Alternative check:
A verification step is to remember that media reports around the launch of GSAT 19, one of the heavy communication satellites, specifically mentioned that it flew on GSLV Mk III. This mission was highlighted as the first developmental flight of India's heaviest rocket and a key step for future human spaceflight plans. GSLV Mk II continued to serve for medium weight satellites, but the heavy milestone missions are associated with Mk III.

Why Other Options Are Wrong:
GSLV Mk II: Although important, it is a medium lift version and not the heaviest vehicle used for landmark heavy communication launches.
GSLV Mk I: An earlier configuration with lower payload capabilities, not the advanced heavy lift rocket referred to in the question.
None of the above: Incorrect because GSLV Mk III clearly fits the description and is a valid option.

Common Pitfalls:
Students sometimes confuse the different GSLV versions or assume that the newest sounding label is always used without checking payload details. Another pitfall is focusing only on the name GSLV without noting the Mk number. Remembering that GSLV Mk III is the heavy lift variant and associated with major milestones like launching heavy communication satellites and preparing for crewed missions will help avoid such confusion.

Final Answer:
Thus, the heavy communication satellite mentioned in the question was launched by ISRO on board GSLV Mk III.