The change in temperature of the coins will depend on the energy they need to do so, this energy depends on the specific heat of the material. The specific heat corresponds to the energy required to raise the temperature of 1 gram of material 1 degree Celsius.
We see that copper has a higher specific heat, therefore, copper will require more energy to raise its temperature and will require more time.
So, the answer will be: C. Copper; requires more energy