Which Is Not an Advantage of Two-Factor Analysis of Variance

Which is not an advantage of two-factor analysis of variance?

A) The number of cases required to answer the questions is less than if the questions had been asked in separate experiments.
B) Interaction between two Factors may be more easily studied.
C) Better experimental control of extraneous variables can be achieved than in a simple experiment.
D) Conclusions regarding the effect of a particular factor apply with wider generality than they would in a simple experiment.