In an X-ray tube, electrons emitted from a filament (cathode) carrying current I hit a target (anode) at a distance d from the cathode. The target is kept at a potential V higher than the cathode resulting in emission I of continuous and characteristic X-rays. If the filament current I is decreased to, the potential difference d V is increased to 2V, and the separation distance d is reduced to , then 2 (A) the cut-off wavelength will reduce to half, and the wavelengths of the characteristic X-rays will remain the same (B) the cut-off wavelength as well as the wavelengths of the characteristic X-rays will remain the same (C) the cut-off wavelength will reduce to half, and the intensities of all the X-rays will decrease (D) the cut-off wavelength will become two times larger, and the intensity of all the X-rays will decrease