which direction does heat flow from?\no hot to cold\no cold to hot\no hot to hot\no cold to cold

Brief Explanations:

Heat always flows from a region of higher temperature (hot) to a region of lower temperature (cold) due to the second - law of thermodynamics which states that in spontaneous processes, entropy of an isolated system increases. Heat transfer from hot to cold increases the overall entropy of the system.

Answer:

A. hot to cold