i don't think the answer could be A. so i pick B.

One reason people around the world use coal as an energy source is:

A. It is nonrenewable.
B. it can be found many places
C. it is a fossil fuel
D. it cannot be used up

Right.

To determine the correct answer, let's analyze the given options.

A. It is nonrenewable: This implies that the availability of coal is limited and it cannot be replenished in a short period of time.

B. It can be found many places: This implies that coal deposits are widely distributed and can be accessed in various locations.

C. It is a fossil fuel: This indicates that coal is formed from the remains of plants and is considered a type of fossil fuel.

D. It cannot be used up: This implies that coal reserves are so vast that they are practically unlimited.

Based on these options, we can conclude that the correct answer is C. It is a fossil fuel, as coal is indeed a type of fossil fuel formed over millions of years.