The Failure Rate of a Contraceptive Method Is Defined As

The failure rate of a contraceptive method is defined as:

A) the percentage of sperm which remain viable 12 hours after use of this method.
B) the number of women out of 100 who become pregnant by the end of the first year of using a particular method.
C) the percentage of people who will experience a breakdown in the method, for example, the number of men out of 100 who will experience a condom breaking.
D) the percentage of people who receive a score of 60% or lower on a written test evaluating their knowledge of a particular method.