150 G of Liquid Nitrogen at Its Boiling Point of 77.0

Multiple Choice

150 g of liquid nitrogen at its boiling point of 77.0 K is stirred into a beaker containing 510 g of 18.0°C water.If the nitrogen leaves the solution as soon as it turns to gas,how much water freezes? The heat of vaporization of nitrogen is 48.0 cal/g and that of water is 80.0 cal/g.

A) none
B) 21 g
C) 42 g
D) 11 g
E) 63 g