Assertion (A) : The pH of a buffer solution containing equal moles of acetic acid and sodium acetate is 4.8 ($pK_a$ of acetic acid is 4.8). Reason (R) : The ionic product of water at $25^{\circ}C$ is $10^{-14}\;mol^{2}.L^{-2}.$

Question

 The correct  answer is : 

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)

(b) Both (A) and (R) are true and (R) is not the correct explanation of A

(c) (A) is true but (R) is not true

(d) (A) is not true but (R) is true.