Evaluate ϕ(pk)\phi(p^k)ϕ(pk) where ppp is prime.
(p−1)k(p-1)^k(p−1)k
pk−pk−1p^k - p^{k-1}pk−pk−1
Both a and b are correct
pk−1(p−1)p^{k-1}(p-1)pk−1(p−1)