Question 1154073
(a)  a l b l a ↑ b   (b)   a l b l (a ↑ b) ↑ (a ↑ b) 
       T  T     F              T  T              T
       T  F     T              T  F              F
       F  T     T              F  T              F
       F  F     T              F  F              F

(c) It is true because the truth table for (b) matches the truth table for a AND b

(d) It is true because the truth table for (a) matches the truth table for a OR b