A non linear function: makes little sense because in real life, variables are related linearly B. is a function with a slope that is not constant C.

A non linear function:

A. makes little sense because in real life, variables are related linearly

B. is a function with a slope that is not constant

C. can be described by a straight line between the dependent and one of the explanatory variables

D. is concept that applies only to the case of a single explanatory variable since you cannot draw aline in four dimensions