In the end of September 2012, India has successfully launched its heaviest communication satellite named

The correct answer is C) GSAT-10. ISRO's GSAT-10 was launched on 29 September 2012 by an Ariane-5 rocket from Kourou, French Guiana. At roughly 3,400 kg it was the heaviest Indian communication satellite of its time, carrying Ku, C and extended C band transponders plus a GAGAN navigation payload. It is a geostationary communication satellite, so the question is really testing your knowledge of the GSAT series.

Why the others fail:

• A) OCEANSAT (IRS-P4): IRS-P4 is the first Oceansat, an ocean-colour and remote sensing satellite launched in 1999. It is an earth observation satellite, not a communication satellite.
• B) LANDSAT-10: Landsat is a US Earth observation programme run by NASA and USGS. There is no Indian LANDSAT-10.
• D) SPOT: SPOT is a French Earth observation satellite series operated by Airbus and CNES, again not a communication satellite.

Core concept: the classification of Indian satellites into communication (INSAT/GSAT), earth observation (IRS, Cartosat, Oceansat) and navigation (IRNSS). This links to Science and Technology and to the Mains theme of space technology for development.

Trap: Candidates pick Oceansat or IRS simply because they are Indian satellites, or choose on the basis of the word "heaviest" without knowing the GSAT series.