Step 1: Identify the core components of a microwave oven and their functions.
B. Magnetron: This is the heart of the microwave oven. It is a vacuum tube that generates the high-frequency microwaves used for heating.
A. Wave guide: This is a rectangular metal tube that directs the microwaves from the magnetron into the oven cavity where the food is placed.
D. Stirrer: This is a fan-like metal blade that reflects and distributes the microwaves within the cavity to ensure more even cooking. In many modern ovens, a rotating turntable serves the same purpose.
C. Channel: This is not a standard technical term for a major component in a microwave oven. The essential components are the magnetron, wave guide, and a method for distributing the waves (stirrer or turntable).
Therefore, A, B, and D are the correct components.