Let $p, q$ and $r$ be three statements. Consider two compound statements
$S_1: \left(p\Rightarrow q\right)\Rightarrow r \equiv p\Rightarrow \left(q\Rightarrow r\right)$
$S_2: \left(p\iff q\right)\iff r \equiv p\iff \left(q\iff r\right)$
State in order, whether $S_1,S_2$ are true or false.

(where, T represents true and F represents false)

• A

  T T
• B

  T F
• Correct answer
  C

  FT
• D

  FF

Hence, the correct answer is option: 'C'.