To evaluate \(\sqrt{15} \times (\sqrt{3})^3\), follow these steps:

1. Simplify \((\sqrt{3})^3\):

\[
(\sqrt{3})^3 = (\sqrt{3})^2 \times \sqrt{3} = 3 \times \sqrt{3} = 3\sqrt{3}
\]

2. Multiply \(\sqrt{15}\) by \(3\sqrt{3}\):

\[
\sqrt{15} \times 3\sqrt{3} = 3 \times (\sqrt{15} \times \sqrt{3}) = 3 \times \sqrt{15 \times 3} = 3 \times \sqrt{45}
\]

3. Simplify \(\sqrt{45}\):

\[
\sqrt{45} = \sqrt{9 \times 5} = 3\sqrt{5}
\]

Thus,

\[
3 \times \sqrt{45} = 3 \times 3\sqrt{5} = 9\sqrt{5}
\]

So the final answer is:

C. \(9\sqrt{5}\)