The orbital module of Gaganyaan consists of:

The correct answer is A, the crew module and the service module. The crew module is the pressurised double walled cabin where the astronauts live, and it is the only part that returns to Earth, protected by a heat shield and lowered by parachutes. The service module is an unpressurised section carrying propulsion, power generation, thermal control and other support systems, and it is separated before re-entry.

Option B, lander and rover, describes Chandrayaan-3, where Vikram and Pragyan worked on the Moon. Option C, orbiter and propulsion module, describes the earlier lunar missions, which had to place a spacecraft in lunar orbit. Option D is wrong because the cryogenic stage belongs to the launch vehicle and burns out long before orbit is reached, so it is never part of the spacecraft. Knowing which part comes back is the detail most often tested.