Correct Option: B

The electron microscope was invented by Max Knoll and Ernst Ruska in 1931 (Germany). An electron microscope uses condensing lenses to focus a beam of electrons to illuminate a specimen and produce a magnified image. An electron microscope (EM) has greater resolving power than a light-powered optical microscope because electrons have wavelengths about 100,000 times shorter than visible light photons. The electron microscope uses electrostatic and electromagnetic “lenses” to control the electron beam and focus it to form an image. These lenses are analogous to but different from the glass lenses of an optical microscope that forms a magnified image by focusing light on or through the specimen.