Answer:
C. All real numbers.
Explanation:
The domain is the set of all x values that are used by points on the graph. This is a sine wave, and we assume it extends infinitely far to the left and right. Even without that assumption, you can eliminate the other answers.
A. This describes the numbers on the x-axis between 0 and 5, inclusive. But the graph includes many more points with x-coordinates beyond that interval.
B. The same sort of thing: the graph extends well beyond the interval of x values between -5 and 5, inclusive.
D. This would mean the graph has only points with positive x-coordinates, but there are many with negative (or 0) x-coordinates.