Which of the following statements is a tautology?

• A
  $\left[ {\left\{ {p \wedge \left( {\left( {q \vee t} \right) \wedge p} \right)} \right\} \to \left\{ {\left( {q \vee r} \right) \wedge \left( {p \vee t} \right)} \right\}} \right] \leftrightarrow \left[ { \sim \left( {q \vee r} \right) \to \sim p} \right]$
• B
  $\left\{ {p \wedge \left( {\left( {q \vee t} \right) \wedge p} \right)} \right\} \leftrightarrow \left[ {\left( {q \vee r} \right) \to p} \right]$
• C
  $\left\{ {p \wedge \left( {\left( {q \vee t} \right) \wedge p} \right)} \right\} \leftrightarrow \left[ {q \wedge r \wedge p} \right]$
• D
  $\left\{ {p \wedge \left( {\left( {q \vee t} \right) \wedge p} \right)} \right\} \leftrightarrow t$ (where $t$ denotes tautology)