To simplify \( 4\sqrt{5} \cdot 2\sqrt{3} \), we can follow these steps:
- Multiply the coefficients: \( 4 \times 2 = 8 \).
- Multiply the radicals: \( \sqrt{5} \cdot \sqrt{3} = \sqrt{15} \).
So the product becomes: \[ 8\sqrt{15} \]
Sandra's answer of \( 8\sqrt{15} \) is indeed correct.
Therefore, the correct choice is:
A. Sandra's simplified answer is correct.