Electrons with energy 80 keV are incident on the tungsten target of an X-ray tube. K shell electrons of tungsten have ionization energy 72.5 keV. X-rays emitted by the tube contain only [IIT-JEE (Screening) 2000]

• A.            A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of  ~ 0.155Å
• B.            A continuous X-ray spectrum (Bremsstrahlung] with all wavelengths
• C.            The characteristic X-rays spectrum of tungsten
• D.            A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of ~ 0.155Å and the characteristic X-ray spectrum of tungsten