The X-ray spectrum coming from an X-ray tube

Question

$\begin {array} {1 1} (a)\;\text{No minimum or maximum wavelengths}\\ (b)\;\text{has all wavelengths smaller than a certain maximum wavelength }\\ (c)\;\text{has all wavelengths greater than a certain maximum wavelength}\\ (d)\;\text{is monochromatic} \end {array}$