Please please be quick to answer and thank you This question from a book : contemporary abstract algebra

Question 7 2.5 pts Let G be a group with |G| = pq, where p and qare prime numbers. Then every proper subgroup of G is cyclic. In the proof of this theorem, which statement of the following is a true statement? Lagrange's theorem tells us that the only possible subgroup is of order pq. There is no any use of Lagrange's theorem in the proof. By Lagrange's theorem, the only possible orders are 1, p, q. We do not need to know that groups of prime orders are cyclic