单选题 Spending the summer traveling round Australia is a great idea, but it begs the ______ of how we can afford it.

【正确答案】 C
【答案解析】[考点] 固定搭配
[解析] beg the question意为“回避问题实质”：是固定短语。mercy意为“仁慈，宽恕”；pleasure意为“愉快，乐趣”；permission意为“许可，允许”。