To simplify the expression \( \frac{5^6}{5^3} \) using the quotient rule of exponents, we can use the rule that states:
\[ \frac{a^m}{a^n} = a^{m-n} \]
Applying this rule, we have:
\[ \frac{5^6}{5^3} = 5^{6-3} = 5^3 \]
Thus, the simplified expression is \( 5^3 \).
The correct response is:
5 cubed (which corresponds to \( 5^3 \)).