Partial pressure of water vapour at dew point temperature of moist air is 1.5 × 10-3 MPa. The barometric pressure is 0.1 MPa. The specific humidity of air is

• A. 15.225 gm/kg da
• B. 9.47 gm/kg da
• C. 15.00 gm/kg da
• D. 9.33 gm/kg da