Suppose You Are Interested in the Effect Watching Television Has

Suppose you are interested in the effect watching television has on creativity. You want to conduct a manipulative experiment, but you realize its disadvantages. You are concerned about all of the following problems, EXCEPT:

A) whether the results will be reliable.
B) whether the treatment is similar to normal conditions.
C) whether your subjects will see themselves as special because you picked them and thus react typically.
D) whether the causes and effects can be determined.