Which of the following describes the number of primitive roots modulo ppp?
ϕ(p)\phi(p)ϕ(p)
ϕ(p−1)\phi(p-1)ϕ(p−1)
p−1p-1p−1
ϕ(ϕ(p))\phi(\phi(p))ϕ(ϕ(p))