这道题答案是B吗？

A certain one-day seminar consisted of a morning session and an afternoon session. If each of the 128 people attending the seminar attended at least one of the two sessions, how many of the people attended the morning session only? (1) 43of the people attended both sessions. (2) 87of the people attended the afternoon session.

c

both吧

我觉得是 B.

参加的人可以分为三种：AM, PM, AM&M.

87of the people attended the afternoon session； 包含了 PM 和 AM&M. 所以余下的就是只参加 AM 的了。