Which of the Following Threats to Internal Validity Is an Example

Multiple Choice

Which of the following threats to internal validity is an example of the problem of experimental mortality?

A) During the implementation of a study on violence in a prison, the prison administrator is replaced
B) During a study, subjects become tired and their response time is affected
C) During a study in which students interview prison inmates, a number of student interviewers graduate and must be replaced
D) During a study comparing two groups of prison inmates, some of the members of one group are released on parole