Consider the Model Described by the Equation $E ( y ) = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } + \beta _ { 3 } x _ { 1 } x _ { 2 }$

Multiple Choice

Consider the model described by the equation $E ( y ) = \beta _ { 0 } + \beta _ { 1 } x _ { 1 } + \beta _ { 2 } x _ { 2 } + \beta _ { 3 } x _ { 1 } x _ { 2 }$ .The slope of the relationship between $E ( y )$ and $x _ { 1 }$

A) is constant for all values of x₂.
B) depends on the value of x₂.
C) depends on the value of x₁.
D) is constant for all values of x₁.