Q. In India, why are some nuclear reactors kept under “IAEA safeguards” while others are not?

Some use uranium and others use thorium
Some use imported uranium and others use domestic supplies
Some are operated by foreign enterprises and others are operated by domestic enterprises
Some are State-owned and others are privately-owned

Answer: (b) Some use imported uranium and others use domestic supplies

The International Atomic Energy Agency (IAEA) is an international organisation dedicated to promoting the peaceful use of nuclear energy and prohibiting its use for military purposes, including the development of nuclear weapons.
International Atomic Energy Agency was established in 1957 and its headquarters are located in Vienna, Austria.
IAEA safeguards are a set of technical safeguards applied by IAEA to independently verify any nuclear facilities to check if it is not misused or deviated from peaceful uses.
Under Article 3 of the Non-Proliferation of Nuclear Weapons Treaty, all the nonnuclear weapon states are required to conclude a safeguard agreement with IAEA.