In India, why are some nuclear reactors kept under "IAEA Safeguards" while others are not?

1. A

   Some use uranium and others use thorium

   Uranium vs thorium. PHWRs use natural U; thorium is not the IAEA split.

2. B

   Some use imported uranium and others use domestic supplies.

   Imported uranium vs domestic. Civil reactors on foreign fuel are under IAEA safeguards; military/unsafeguarded plants use domestic fuel.

3. C

   Some are operated by foreign enterprises and others are operated by domestic enterprises

   Foreign vs domestic operators. NPCIL runs both kinds.

4. D

   Some are State-owned and others are privately-owned

   State vs private. Nuclear generation is not a private-operator split here.

Summary. Official key is (b). After the Indo-US civil nuclear deal, imported-fuel civil reactors are placed under IAEA safeguards. Reactors on the military/unsafeguarded list use domestic uranium and are not.