The conductivity of $0.001 \mathrm{M}$ acetic acid at a certain temperature is $5.07 \times 10^{-5} \mathrm{~S} \mathrm{~cm}^{-1}$. If $\wedge_m^0$ of acetic acid at the same temperature is $390 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$, the dissociation constant of acetic acid at that temperature is:

• Correct answer
  A

  $1.94 \times 10^{-5}$
• B

  $1.94 \times 10^{-3}$
• C

  $1.94 \times 10^{-4}$
• D

  $1.94 \times 10^{-6}$

Hence, the correct answer is option: 'A'.