A 12.5-g sample of granite initially at 82.0 °C is immersed into 25.0 g of water initially at 22.0 °C. What is the final temperature of both substances when they reach thermal equilibrium? (For water, C_s = 4.18 J/g # °C and for granite, C_s = 0.790 J/g · °C.)

a) 52.0 °C 

b) 1.55 * 10³ °C 

c) 15.7 °C 

d) 27.2 °C