At a certain temperature, dissociation constant of formic acid and acetic acid are $1.8 \times 10^{-4}$ and $1.8 \times 10^{-5}$ respectively. At what concentration of acetic solution, the $H_3O^+$ ion concentration is same as that in 0.001 M fromic acid solution

Question

(a) 0.01 M

(b) $1 \times 10^{-3}$ M

(c) $1 \times 10^{-1}$ M

(d) $1 \times 10^{-4}$ M