Which statement best captures the primary conceptual distinction between a one-factor ANOVA and a two-factor ANOVA with interaction?

• A. One-factor ANOVA tests one factor's main effectTwo-factor ANOVA tests two factors' main effects without interaction
• B. One-factor ANOVA tests interactionsTwo-factor ANOVA tests only main effects
• C. One-factor ANOVA tests one factorTwo-factor ANOVA tests both factors and their interaction.
• D. One-factor ANOVA compares two groupsTwo-factor ANOVA compares more than two

Answer: (C)