Recall the standard form of the Master Theorem and identify the critical condition where the regular case applies (i.e., when \( f(n) = O(n^{\log_b a - \epsilon}) \) for some \( \epsilon > 0 \)).

Compare the given function \( f(n) = cn^k \) with \( n^{\log_b a} \) and determine the relationship between \( k \) and \( \log_b a \) under the condition \( a > b^k \).

Use the **regularity condition** of the Master Theorem to justify why the solution \( t(n) = \Theta(n^{\log_b a}) \) holds, even when \( f(n) \) is not polynomially smaller than \( n^{\log_b a} \).