Including an Interaction Term Between Two Independent Variables, X₁ and X₂

Multiple Choice

Including an interaction term between two independent variables, X₁ and X₂, allows for the following except:

A) the interaction term lets the effect on Y of a change in X₁ depend on the value of X₂.
B) the interaction term coefficient is the effect of a unit increase in X₁ and X₂ above and beyond the sum of the individual effects of a unit increase in the two variables alone.
C) the interaction term coefficient is the effect of a unit increase in $\sqrt { \left( X _ { 1 } \times X _ { 2 } \right) }$
D) the interaction term lets the effect on Y of a change in X₂ depend on the value of X₁.