B - Incorrect: The preposition where can only be used to describe places, not objects.

C - Incorrect: Inserting this answer choice into the sentence results in the adverb presently to be misplaced.

D - Incorrect: Inserting this answer choice into the sentence results in the adverb presently to be misplaced. Also, replacing and with or changes the meaning of the sentence.

E - Incorrect: The elimination of a pronoun introduces ambiguity.

A- Correct. in which is a properly used relative pronoun with a preposition, and the prepositional phrase is properly followed by a complete clause.

A is the correct answer.