This device is a burner from an electric stove. It is used to transfer heat to a pot by

A. Conduction

B. Convection

C. Radiation

D. Friction

Convection.

Definition of Convection:

con·vec·tion

the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.