Final answer:
The cardinality of the set of English names for the months of the year is 12.
Step-by-step explanation:
The question asks about the cardinality of the set P, which is the set of English names for the months of the year. Cardinality refers to the number of elements in a set. In this case, since there are 12 months in a year, the set of English names for these months would have 12 elements. Therefore, the cardinality of set P is 12.