Question: Let H=\{e,(12)(34)\} and K=\{e,(12)(34),(13)(24),(14)(23)\} be subgroup of S_4, where e denotes the identify element of S_4. Then
H and K are normal subgroup of S_4
H is normal in K and K are normal in A_4
H is normal in A_4 but not in S_4
H is normal in S_4 but H is not
Answer: Recall
Conjugation preserve disjoint cyclic structure in permutation group, i.e., for all \sigma, \tau \in S_n, the disjoint cyclic decomposition of \tau and \sigma \tau \sigma^{-1} will be the same.
Since K contain all element with...