Answer: The answer is C.
A Linear parent function is a function of the form f(x) = x
or y = x. This is the simplest of the linear functions, where the slope is 1 and the function pases for the point (0,0) (which is the same of saying that the intercept is 0).
a) isnt a linear function.
b) is a quadratic function.
d) is also a linear function, but it has a slope = 2, so it isn't the linear parent function.