According to the First Law of Thermodynamics, which of the following statements best describes the relationship between heat (Q), internal energy change (ΔU), and work done (W) in a closed system?

A、The total energy of the system increases with the addition of heat, regardless of work done.
B、The energy of a closed system can be created from nothing if heat is supplied.
C、The heat added to the system is equal to the sum of the change in internal energy and the work done by the system.
D、In a closed system, work done is always negative when heat is added to the system.