Andrew's principal place of business is his home office. Andrew may deduct expenses related to the use of his home office only if which of the following is true?

A. It is accessible to the public through a separate entrance.

B. The office contributes substantially to the profitability of his business.

C. The office is usedexclusively and regularly for purposes related the Andrew's business.

D. The use of a separate office must be a generally accepted practice in Andrew's field of business.