Final answer:
A. Air Ejector
Step-by-step explanation:
The correct answer is A. Air Ejector. The other options - Inter Condenser, Direct Contact Heater (DC Heater), and Plate Heat Exchanger - are all types of heat exchangers.
A heat exchanger is a device used to transfer heat between two or more fluids or between a solid surface and a fluid. It helps in efficiently transferring heat from a hotter fluid to a cooler fluid, without mixing the two fluids.
For example, a plate heat exchanger consists of a series of plates with alternating hot and cold fluids flowing between them. The heat is transferred from one fluid to the other through the plates, without the fluids mixing.