To convert pounds to ounces, we use the conversion factor that 1 pound is equal to 16 ounces.
First, we need to convert \( 2 \frac{3}{4} \) pounds to a fraction:
- Convert \( \frac{3}{4} \) to a decimal: \( 2 \frac{3}{4} = 2 + 0.75 = 2.75 \) pounds.
Now, we calculate the total ounces: \[ 2.75 \text{ pounds} \times 16 \text{ ounces per pound} = 44 \text{ ounces} \]
Thus, Ravi buys 44 ounces of flour. Therefore, the correct answer is: D. 44 ounces.