Let's break down the information provided:
- Let \( D \) be the total number of donuts at the shop.
- According to the problem, \( \frac{1}{2} \) of the donuts have frosting. Therefore, the number of donuts with frosting is: \[ \frac{1}{2} D \]
- Of the donuts with frosting, \( \frac{3}{4} \) have sprinkles. To find the number of donuts that have both frosting and sprinkles, we take \( \frac{3}{4} \) of the donuts with frosting: \[ \frac{3}{4} \times \frac{1}{2} D = \frac{3}{8} D \]
So, the number of donuts that have both frosting and sprinkles is \( \frac{3}{8} D \).
Since the answer choices do not specify \( D \) and it appears we need the fractional part independent of \( D \), we can state that:
\[ \text{The fraction of donuts with both frosting and sprinkles is } \frac{3}{8}. \]
Thus, the answer is:
3/8