______ is the effect of an independent variable on the dependent variable within a factorial research design, while ______ are the means in the table that represent the main effect.

A) Interaction effect; marginal means
B) Interaction effect; cell means
C) Main effect; marginal means
D) Main effect; cell means

The main effect is the effect of an independent variable on the dependent variable within a factorial research design. Marginal means are the means in the table that represent the main effect, as they represent the means of each level of the independent variable collapsed across the levels of the other independent variable. Cell means, on the other hand, represent the means of each combination of levels of the two independent variables and are used to calculate the interaction effect. Therefore, option C is the correct answer.