<span>C. Youthful
"Child-like" as a word can best be replaced by the adjective youthful. It is the correct part of speech to fit into the rest of the sentence, and it means basically the same thing. Acting like a child is acting as one did in youth, so youthful and child-like are very close synonyms. </span>
The answer is all of the above except choice 3.
In a business setting, you never want to use a detached tone. This gives the impression to your colleague/boss/etc. that you don't care and don't really want to be there. It shows that you don't see them as important and don't care about what they have to say. It won't achieve anything for you.
A. Joey isn't moving to Denver after all.
