A glass initially contains 100 g of ice and 50 g of water. The ice, the water, the glass and the air surrounding them are all at T = 0 °C and P = 1 atm. The water is evaporating very gradually. Which of the following is true?
a. The ice and water are at equilibrium with each other and with the surroundings.
b. The ice and water are not in equilibrium with each other, but if 25 g of ice melted, making the masses of the ice and water equal, they would then be in equilibrium with each other.
c. The water is in thermal and mechanical equilibrium with the air, but not in chemical equilibrium.
d. The system is at steady state but not in equilibrium.
e. None of the above are true.