Which questions should be asked to assess the validity of the claim ?

[PlAwAnSaI]

A customer calls complaining about the level of service being received. The customer produces a log showing service-level measurements that were collected over the past week. Which three questions should be asked at a minimum in order to assess the validity of the claim? (Choose three.)

A. Who took the measurements?
B. How were the measurements taken?
C. Why were the measurements taken?
D. Are the measurements statistically relevant?
E. What were the measurements taken?