Question

the first suspect was nonchalant as she sauntered into the interrogation room for questioning. \where were you on the night of june 13, 2013?\ detective crawford asked her. unconcerned, she responded, \i was the keynote speaker at an event that night, and several hundred people who were in attendance can corroborate my alibi.\ calm and tranquil appearing innocent unpredictable

Explanation:

To determine the meaning of "nonchalant", we analyze the context. The suspect "sauntered" (walked casually) into the room and was "unconcerned" in her response. "Calm and tranquil" aligns with this relaxed, unconcerned demeanor. "Appearing innocent" focuses on innocence, not the tone of being unconcerned. "Unpredictable" refers to being erratic, which doesn't match the context of a relaxed, unconcerned attitude.

Answer:

calm and tranquil