When using not only . . . but also in a sentence, parallelism should be the goal. It means that the words following both parts of this correlative conjunction (i.e., not only and but also) should belong to the same parts of speech. For example, if a verb follows not only, then a verb should also follow but also. Using different parts of speech after each part of not only . . . but also makes the sentence imbalanced and, frankly, just awkward. Hence, Option C is correct. The rest of the options do not adhere to this rule, hence, incorrect.