Final answer:
The objective lens of a compound light microscope magnifies the specimen; this magnified image is then enlarged by the eyepiece.
Step-by-step explanation:
The part of a compound light microscope that is responsible for magnifying the specimen is the objective lens. The objective lens is the first lens that the light passes through after coming from the specimen and is primarily responsible for creating a magnified image of the specimen. This magnified image is then further enlarged by the eyepiece (also known as the ocular lens). Both the objective lens and the eyepiece contribute to the overall magnification of the microscope. The stage supports the specimen, and the base provides stability, but neither is involved in magnification. Therefore, the correct answer is b) Objective lens.