Anthony’s performance has been lower in the last six months than his average in the previous three years. Anthony’s supervisor wants to understand why Anthony’s performance is slipping. It is obvious that Anthony’s ability has not changed, so the supervisor must consider all of the following factors EXCEPT

a. whether Anthony is having trouble working with new job software.

b. if Anthony's new co-workers are poor performance.

c. whether the supervisor herself has changed how she manages Anthony.

d. if Anthony’s capabilities have changed.