Which part of a dental X-ray machine produces electrons?

In an X-ray tube, the CATHODE (negative electrode) contains a tungsten filament that, when heated by electrical current, releases electrons through THERMIONIC EMISSION. These electrons are accelerated toward the ANODE (positive electrode) where they strike the tungsten target and produce X-rays. The anode produces X-rays (not electrons — A wrong). The window allows X-ray exit (C wrong). The lead glass provides shielding (D wrong). B (cathode) is correct.