A 2.75-g copper coin at 15.0°C drops 45.0 m to the ground. Assuming 70.0% of the change in gravitational potential energy of the coin–earth system goes into increasing the internal energy of the coin, determine the coin's final temperature.

a) 26.5°C
b) 32.1°C
c) 40.8°C
d) 50.2°C