---What’s made Ruth so upset?--- three tickets to the folk music concert.A. LostB. Losing

问题补充：

---What’s made Ruth so upset?

--- three tickets to the folk music concert.

A. Lost

B. Losing

C. Because of losing

D. Since she lost

答案：

A. Lost

(答案→)B. Losing

C. Because of losing

D. Since she lost

解析：根据问句：什么使如斯如此伤心呢？可推断出示对主语进行提问，从四个选项中可以看出B. Losing可做主语，其余三项不能，所以选B。