Suppose That the Sample Regression Equation of a Model Is $\tilde { y } = 10 + 4 x _ { 1 } + 3 x _ { 2 } - x _ { 1 } x _ { 2 }$

Suppose that the sample regression equation of a model is $\tilde { y } = 10 + 4 x _ { 1 } + 3 x _ { 2 } - x _ { 1 } x _ { 2 }$ .If we examine the relationship between x₁ and y for three different values of x₂,we observe that the:

A) three equations produced differ not only in the intercept term but also the coefficient of x₁ varies.
B) coefficient of x₂ remains unchanged.
C) coefficient of x₁ varies.
D) three equations produced differ only in the intercept.