If a line has seven feet, a poem is written in
trimeter
tetrameter
pentameter
heptameter

true. the definition explains it: a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, degree, etc. this is a dictionary definition that i have looked up in a dictionary.

answer: the first one

explanation:

explicitly is defined as “in a clear and detailed manner, leaving no room for confusion or doubt.” the rest are interpretive and not clearly proven leaving in fact possible “confusion or doubt” which explicitly, by definition cannot have.