.The only sentence that contains a parallel structure is option B. Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal
Options A,C and D are not ´parallel structures because they do not carry the same tense
Parallel structure means that the items included in a list must be in the same form, in this case all main verbs are in the past simple
