Answer:
C: 8.15%
Explanation:
The best way to figure this out in my opinion is using variables.
Let's say stock = x.
During the first half, the stock increased by 5%, which means the new stock is 1.05x.
During the second half, the new stock increased by 3%, which means the new new stock is 1.05 * 1.03 * x = 1.085x.
1.0815x is the same as saying something has increased by 8.15%, which is one of our answers!