A generic solid X has a molar mass of 65.9 g/mol. In a constant-pressure calorimeter, 31 g of X is dissolved in 381 g of water. What is the final temperature of the solution if the initial temperature of both X and water was 25°C?

a) 26.5°C
b) 27.3°C
c) 28.1°C
d) 29.0°C