2. which of the following is true of functions and their inverses?
a. the inverse of a quadratic function is not a function.
b. the inverse of a linear function is always a function.
c. the inverse of a quadratic function is always a function.
d. the inverse of a linear function is not a function.

Answer – A. (The inverse of a quadratic function is not a function)
Since a parabola (quadratic function) does not pass the horizontal line test, it is not possible for a quadratic equation to will have an inverse that is also a function.

Option B is wrong because the inverse of a linear function is not always a function because when the linear function has slope, the inverse cannot be a function. 
Option C is wrong because the inverse of a quadratic function is never a function because a quadratic function does not pass the horizontal line test
Option D is wrong because the inverse of a linear function is a function, provided that the linear function has no slope.