Answer:
(C) 1
Explanation:
In a function, a real zero is where the function is equal to zero, or:

which can be rewritten as:

which is essentially the y-intercept.
Recall that the y-intercept of a graph is where the graph crosses the y-axis (the x-coordinate is equal to 0).
We can see that the graph only crosses the y-axis at one point, meaning it only has one y-intercept, meaning it has only one real zero.
Thus, the answer is (C), 1