【正确答案】 D

【答案解析】[听力原文]
   M: What have you been doing these past five years?
   W: How time flies! It has been five years since we graduated from this school.
   Q: What is the probable relationship between the two speakers?
[考点] 推断人物关系
此题的关键是女士回答中的“since we graduated”，表明他们以前应该是同学，故选D。