The dry-bulb and wet-bulb temperatures are measured in atmospheric air to be 25 8C and 20 8C,

Question:

The dry-bulb and wet-bulb temperatures are measured in atmospheric air to be 25 8C and 20 8C, respectively. If the atmospheric pressure is 100 kPa, the humidity ratio is nearest:
(A) 0.0129 kg vapor/kg dry air
(B) 0.0128 kg vapor/kg dry air
(C) 0.0127 kg vapor/kg dry air
(D) 0.0126 kg vapor/kg dry air