100 G of Liquid Nitrogen at Its Boiling Point of 77

Multiple Choice

100 g of liquid nitrogen at its boiling point of 77 K is stirred into a beaker containing 600 g of 15°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 cal/g and that of water is 80 cal/g.

A) none
B) 29 g
C) 68 g
D) 109 g