To simplify \(5^{10} \cdot 5^{5}\) using the Product Rule of Exponents, you add the exponents. The Product Rule states that:
\[ a^m \cdot a^n = a^{m+n} \]
In this case, \(m = 10\) and \(n = 5\):
\[ 5^{10} \cdot 5^{5} = 5^{10 + 5} = 5^{15} \]
So the simplified expression is \(5^{15}\).
The correct answer is \(5^{15}\).