H₂S gas is used in qualitative analysis of inorganic cations. Its solubility in water at STP is 0.195molKg⁻¹. Thus, Henry's law constant (in atm molal⁻¹) for H₂S is
A. 2.628×10⁻⁴
B. 5.128
C. 0.185
D. 3.826×10³