SAT Mathematics Practice Test 2

The definition of the graph of a function f in the $\mathit{x}\mathit{y}-$plane is the set of all points $\left(\mathit{x},\mathit{f}\left(\mathit{x}\right)\right)$. Thus, for $-4\le \mathit{a}\le 4$, the value of $\mathit{f}\left(\mathit{a}\right)$ is 1 if and only if the unique point on the graph of f with x-coordinate a has y-coordinate equal to 1. The points on the graph of f with x-coordinates $-4,\frac{3}{2}$, and 3 are, respectively, $\left(-4,1\right),\left(\frac{3}{2},1\right)$ and $\left(3,1\right)$.Therefore,all of the values of f given in I,II and III are equal to 1
Choices A, B, and C are incorrect because they each omit at least one value of x for which $\mathit{f}\left(\mathit{x}\right)=1.$