Answer:
The correct option is:
A) by direct or indirect contact between objects at different temperatures
Step-by-step explanation:
Heat can be transferred in three different methods:
Conduction, Convection and Radiation
Conduction is heat transfer through direct contact between substances at different temperatures.
Convection is the heat transfer which takes place through air currents.
Radiation is the heat transfer that does not require contact between two objects.
Hence, heat transfer can take place through direct or indirect contact between objects at different temperatures.