To simplify \( \sqrt[3]{125} \):
We can express 125 as \( 5^3 \) because \( 5 \times 5 \times 5 = 125 \).
Now we can rewrite the expression:
\[ \sqrt[3]{125} = \sqrt[3]{5^3} \]
Using the property of radicals that \( \sqrt[n]{a^n} = a \), we get:
\[ \sqrt[3]{5^3} = 5 \]
Thus, \( \sqrt[3]{125} = 5 \).
The correct answer is \( \boxed{5} \).