In a and b option we are not getting unique subgroups then how normal

5. (A) Let G be a group of order 56. Then, all 7-sylow subgroups of G are normal. all 2-sylow subgroups of G are normal. (C) there is a proper normal subgroup of G. (B) either a 7-sylow Subgroups or a 2-sylow subgroup of G is normal. (D)