In Which Process Is ΔH = ΔU

In which process is ΔH = ΔU?

A) Two moles of ammonia gas are cooled from 325°C to 300°C at a constant pressure of 1.2 atm.
B) One gram of water is vaporized at 100°C and 1 atm.
C) Two moles of hydrogen iodide gas react to form hydrogen gas and iodine gas in a 40-L container.
D) Solid calcium carbonate is heated to form solid calcium oxide and carbon dioxide gas in a container with variable volume.
E) One mole of solid carbon dioxide sublimes to the gas phase.