If gcd(a,n)=1\gcd(a, n) = 1gcd(a,n)=1, which of the following is an application of Euler's Theorem?
aϕ(n)≡1(modn)a^{\phi(n)} \equiv 1 \pmod{n}aϕ(n)≡1(modn)
an≡1(modn)a^{n} \equiv 1 \pmod{n}an≡1(modn)
an−1≡1(modn)a^{n-1} \equiv 1 \pmod{n}an−1≡1(modn)
aϕ(n)−1≡1(modn)a^{\phi(n)-1} \equiv 1 \pmod{n}aϕ(n)−1≡1(modn)