If events A and B are compatible, how do we calculate the probability of their disjunction?

A) Subtract the probability of A from the probability of B.
B) Add the probability of A to the probability of B.
C) Add the probability of A to the probability of B and then subtract the probability of A and B both occurring.
D) Multiply the probability of A by the probability of B.
E) Divide the probability of A by the probability of B.

When events A and B are compatible, it means they can both occur at the same time. In this case, we can calculate the probability of their disjunction (either A or B occurring) by adding the probability of A to the probability of B and then subtracting the probability of A and B both occurring. This is because if we simply add the probabilities of A and B, we will be double-counting the probability of both A and B occurring. Therefore, option C is the correct choice.