Which word could best replace either the underlined phrase or word in the paragraph?

I’ve been volunteering for a dog rescue group and was asked to speak at a charity event. At first I said I would be glad to do it, but on the night of the event, I started to get butterflies in my stomach. As I practiced my speech, I got even more nervous. Once I began speaking though, I became more relaxed.

A.
troubled

B.
comfortable

C.
sick

D.
anxious