With reference to radioisotope thermoelectric generators (RTGs), consider the following statements: 1. RTGs are miniature fission reactors. 2. RTGs are used for powering the onboard systems of spacecraft. 3. RTGs can use Plutonium-238, which is a by-product of weapons development. Which of the statements given above are correct?

2 and 3 only

Statement 1 is incorrect because RTGs are not fission reactors. They convert heat released by radioactive decay directly into electricity through thermoelectric materials; they do not sustain a nuclear fission chain reaction. Statement 2 is correct because RTGs provide reliable long-duration electrical power for spacecraft, especially missions operating far from the Sun. Statement 3 is accepted as correct in the context of the question: Plutonium-238 is used in RTGs and has been produced in nuclear-reactor programmes associated with nuclear-weapons-related infrastructure, although it is not itself a direct fission by-product. Hence, statements 2 and 3 are taken as correct. Option A incorrectly includes Statement 1 and excludes Statement 3. Option C includes the incorrect Statement 1 and excludes the correct Statement 2. Option D is incorrect because Statement 1 is false.