If P(A) = 0.45, P(B) = 0.55, and P(A ∪ B) = 0.78, then P(A | B) =

A) 0.00
B) 0.45
C) 0.22
D) 0.40

P(A ∪ B)

The probability that at least one of two events, A or B, occurs, including the possibility that both events occur simultaneously.

P(A | B)

Conditional Probability of A given B, representing the probability of event A occurring given that event B is known to occur.