53.

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

Each is used as an apposition to further explain doors, and B is correct.

Item A: The full stop is not a complete sentence, wrong.

Item C: in which leads the attributive clause, the antecedent department cannot be an adverbial in the clause, and the semantics are wrong.

Item D: There is no parallel content before and after the cause of the error.