I feel very excited _____the thought of joining my family in a w

I feel very excited _____the thought of joining my family in a week.
A、on
B、for
C、at
D、in
【正确答案】：C
【题目解析】：考查固定短语。句意：一想到一周后就能和家人在一起，我就很激动。be excited at sth.意为“对某事感到兴奋”，故选C。