She was about to phone her boss and admit that she ______ not thought of anything.

• A. Had
• B. Has
• C. Having
• D. Have

Answer: (A)

This sentence tests using the past perfect to describe something that hadn’t happened before a past moment. “Was about to phone” places us in a past moment, and what she admits is true before that moment—she had not thought of anything. So the natural sequence is: she was about to phone and admit that she had not thought of anything. The past perfect “had not thought” shows the prior state.

Other forms don’t fit because they don’t align with the past context. “Has not thought” uses the present perfect, which connects to the present, not to that past moment. “Having not thought” is a participle form that doesn’t work as the main verb in this clause. “Have not thought” is the present perfect and would not correctly place the action before the past moment described by “was about to.”