The structure as…as is used to compare things that are of similar proportion. In this case the firstasacts as an adverb modifying the adjective or adverb that goes after it. The second as can act as a preposition or conjunction. If it is used as a conjunction, it will be followed by a clause. Here, the second "as" is used as a conjunction which means it should be followed by a noun/pronoun+ verb. The sentence does not contain a verb in the second clause, rendering it grammatically incorrect. Hence, Option A is correct.