What is the molality of ammonia in a solution containing 0.85 grams of NH₃ in 100 ml of a liquid of density of 0.85 g cm⁻³?

A. 0.588 mol kg⁻¹
B. 5.88 mol kg⁻¹
C. 0.0588 mol kg⁻¹
D. None of these