S1:$ ^{\sim} (p \leftrightarrow\: ^{\sim} q)$ is equivalent to $p \leftrightarrow q.$ \[\] S2 :$ ^{\sim} (p\leftrightarrow \: ^{\sim} q)$ is a tautology.

Question

$\begin {array} {1 1} \text{(A) S1 is true, S2 is true,S2 is a correct explanation for S1} \\ \text{(B) S1 is true, S2 is true, S2 is not a correct explanation for S1} \\ \text{(C) S1 is true, S2 is false} \\ \text{(D) S1 is false, S2 is true} \end {array}$