The _____failure rate of a contraceptive method is the probability of conception when the method is used correctly.

A) ideal
B) typical
C) consistent
D) prescribed

The ideal failure rate is the probability of conception when the method is used correctly. This means that the method is used consistently and as instructed, without error or misuse. The typical failure rate, on the other hand, includes cases where the method is not used correctly, such as skipping a pill or using a condom incorrectly. Consistent and prescribed are not commonly used terms in the context of contraceptive methods.