CONFUSION

(A) because CF3 is an EWG whereas CH3 is ERG

the answer is (A) because the EWG CF₃ stabilizes the anion in the conjugate base, thereby making the conjugate base stable enough to prevent backward reaction ...hence it is a weak conjugate base because it is stable enough by itself and hence does not like to accept a proton ! as we know that a weak conjugate base has a stronger acid ,hence (A) is the correct answer ! think logically in the same way to deduce that the EDG does the opposite thing !