单选题 Ms. Shirish will resign her position as chief ______officer.

A、 (A) operator
B、 (B) operational
C、 (C) operation
D、 (D) operating

【正确答案】 D

【答案解析】Operating forms part of the title chief operating officer. Choice (A) is a noun referring to people. Choice (B) is an adjective but is not used in this title. Choice (C) is a noun that refers to things.