To find:
Which of the given statements is true?
Step-by-step explanation:
Thermal equilibrium is a state that may exist between two objects when the net flow of heat between them is zero.
When two objects at different temperatures are kept in contact, the heat flows from the hot object to the cold object. This happens until the net heat flow between them becomes zero. At this stage, both objects that are in contact will be having the same temperature.
Thus two objects are said to be in thermal equilibrium if they are at the same temperature.
Final answer:
Thus the correct answer is option D.