To simplify \(\frac{k^{120}}{k^{30}}\), you can use the rule of exponents that states \(\frac{a^m}{a^n} = a^{m-n}\).
Applying this rule:
\[ \frac{k^{120}}{k^{30}} = k^{120 - 30} = k^{90} \]
So, the simplified expression is \(k^{90}\).
Thus, the correct response is k90 (k to the 90th power).