Identify the predicate among the choices below:
a. the monster cage in my room
b. my hockey sock
c. henrietta the dog sitter
d. lived behind the gas station

From the choices stated above, the predicate is letter (D.) lived behind the gas station. Predicate is the part of a sentence which includes the verb and tells something about the subject. In this case, the verb is "lived", and it is followed by a prepositional phrase which indicates location.