Suppose That the Sample Regression Equation of a Model Is

Suppose that the sample regression equation of a model is = 10 + 2x₁ + 3x₂ - x₁x₂.If we examine the relationship between x₁ and y for four different values of x₂,we observe that the:

A) four equations have different coefficients of x₁.
B) four equations produced differ only in the intercept term.
C) coefficient of x₂ remains unchanged.
D) coefficient of x₁ remains unchanged.