If all the points for a multiple regression model with two independent variables were on the regression plane, then the multiple coefficient of determination would equal:
A. 2, since there are two independent variables
B. any number between 0 and 2
C. 1
D. 0

The graphical depiction of the equation of a multiple regression model with $k$ independent variables $k>1$ is referred to as:
A. a response surface
B. a plane only when $k=3$
C. a straight line
D. a response variable