Which of the Following Is Not One of the Reasons

Which of the following is not one of the reasons that single-case designs are more popular than control group designs among behavior modifiers?

A) Single-case designs typically provide potentially valuable information on individual variation in performance.
B) Single-case designs are based on assumptions about the distribution of the dependent variable in the population.
C) Single-case designs require only a few individuals with the same performance problem in order to evaluate an intervention.
D) In single-case designs, all of the clients receive the treatment at one time or another.