The dissociation constants of four monobasic acids HA, HX, HY and HD are respectively $6 \times 10^{-4}, 5 \times 10^{-5}, 3.6 \times 10^{-6}, 7 \times 10^{-10}$. The $pH$ values of their 0.1 M aqueous solutions is

Question

(a) HA > HX > HY > HD

(b) HD > HY > HX > HA

(c) All the solutions have same $pH$

(d) HX > HD > HY > HA