Question

what is the primary fuel used in nuclear reactors? natural gas uranium oil coal

Explanation:

Nuclear reactors use uranium as their primary fuel. Natural gas, oil, and coal are fossil fuels used in other types of power generation (like gas - fired plants, oil - fired plants, and coal - fired plants), not nuclear reactors.

Answer:

B. uranium (assuming the second option is labeled B, as per the options: natural gas (A), uranium (B), oil (C), coal (D))