The probability of an event is 0.001. Which of the following best describes the event?

A The event will never occur.

B There is a small chance that the event will occur.

C The event is likely to occur.

D The event will definitely occur.

The answer you are looking for is B, there is a small chance of the event occurring.

B. There is a small chance that the event will occur.

C and D are definitely wrong since 0.001 is equal to 0.1%, that's not even 1%.

But even though it's small, that doesn't mean it's impossible, just highly unlikely.

So the answer is B.