Answer:
C. I stood in the open door of my boss's office, frozen despite the butterflies doing acrobatics in the pit of my stomach.
Explanation:
A. Unlike C, this answer almost seems to provide a dismissive tone of their nervous feeling. They seemed to have some form of composure, as they could at least shake her hand. This answer can be eliminated.
B. Here, the sentence directly states that they feel their tension ease itself. They do not seem very nervous, but it could still be a possibility. However, there is a better answer.
C. Here, an idiom is used to describe the state of the person in question. The "butterflies in their stomach" is a common English expression to express anxiety or worry. Clearly, this is the correct answer.
D. This answer is descriptive of the scenery, but it does not mention a word of the person's feelings. This answer can be easily eliminated.
