The molar conductivity of $0.01 \text{ M}$ monobasic acid at $25 \text{ }^\circ\text{C}$ is $15 \text{ ohm}^{-1} \text{cm}^2 \text{mol}^{-1}$. The molar conductivity of the same acid at infinite dilution is $375 \text{ ohm}^{-1} \text{cm}^2 \text{mol}^{-1}$. Calculate $[H^+]$ in solution.

• A
  $4 \times 10^{-4} \text{ M}$
• B
  $5 \times 10^{-4} \text{ M}$
• C
  $2 \times 10^{-4} \text{ M}$
• D
  $3 \times 10^{-4} \text{ M}$