To find:
What kind of a system is the water heater?
Step-by-step explanation:
In an open system, the matter and the energy of the system are exchanged between the system and its surrounding.
In a closed system, only the energy of the system is exchanged with the surroundings and the matter is not exchanged.
In an isolated system, neither energy nor matter is exchanged with the system and the surrounding.
A hot water heater is designed to intake cold water and give hot water as output. That is, the water, a matter, is exchanged between the heater and the surrounding. And the energy in the form of heat is also exchanged between the heater and the surrounding.
Thus the hot water heater is an open system.
Final answer:
The hot water heater is an open system.
Thus the correct answer is option A.