Question
      
        If the Boolean expression $$\left( {p \oplus q} \right) \wedge \left( { \sim p \odot q} \right)$$    is equivalent to $$p \wedge q,$$  where $$ \oplus , \odot  \in \left\{ { \wedge , \vee } \right\}$$   then the ordered pair $$\left( { \oplus , \odot } \right)$$  is:                                
       A.
        $$\left( { \vee , \wedge } \right)$$              
       B.
        $$\left( { \vee , \vee } \right)$$              
       C.
        $$\left( { \wedge , \vee } \right)$$                 
              
       D.
        $$\left( { \wedge , \wedge } \right)$$              
            
                Answer :  
        $$\left( { \wedge , \vee } \right)$$      
             Solution :
        Check each option
$$\eqalign{
  & \left( 1 \right)\,\,\left( {p \vee q} \right) \wedge \left( { \sim p \wedge q} \right) = \left( { \sim p \wedge q} \right)  \cr 
  & \left( 2 \right)\,\,\left( {p \vee q} \right) \wedge \left( { \sim p \vee q} \right) = \left( {p \wedge  \sim p} \right) \vee q  \cr 
  &  = F \vee q = q  \cr 
  & \left( 3 \right)\,\,\left( {p \wedge q} \right) \wedge \left( { \sim p \vee q} \right) = \left( {p \wedge q \wedge  \sim p} \right) \vee \left( {p \wedge q} \right) \wedge q  \cr 
  &  = F \vee \left( {p \wedge q} \right) = p \wedge q  \cr 
  & \left( 4 \right)\,\,\left( {p \wedge q} \right) \wedge \left( { \sim p \wedge q} \right) = \left( {p \wedge  \sim p} \right) \wedge q  \cr 
  &  = F \sim q = F \cr} $$