Let $G$ be a group of order $56$. Then which of the following are true
- All $7$-sylow subgroups of $G$ are normal
- All $2$-Sylow Subgroups of $G$ are normal
- Either a $7$-Sylow subgroup or a $2$-Sylow subgroup of $G$ is normal
- There is a proper normal subgroup of $G$.
How would I able to solve this problem and which theorem(s) would be required to solve this? Thanks for your time.