Answer:
Graph C
Step-by-step explanation:
The book is in free fall (no air resistance), this means that it is subject to a constant acceleration,

downward, which is the acceleration of gravity.
Therefore, taking downward as positive direction, its position at time t will be given by

where t is the time.
We see that the equation above represents a parabola: the only graph representing a parabola is graph C), therefore this is the correct option.