An atom with vacancy has higher energy than a neutral atom. So, (A) is incorrect.
K X-ray is created when a vacancy (hole) is filled in the K shell by an electron jumping from the successive shell to k-shell. So, the hole or vacancy is created in the shell where the electron jumps from. Hence, option (B) is correct.
Characteristic K X-rays are produced when an electron from subsequent L, M, and N… shells drops to fill the vacant K shell. The energy of this transition is greater than the energy of transition form M, N, O… to L shell. Wavelength is inversely promotional to energy. So, KX rays have shorter wavelengths.
The wavelengths for K and K are given as:

where, λ_α and λ_β are the wavelength, h is the Planck’s constant(6.62607004 × 10^-34 m² kg / s), c is the speed of light in vacuum, E_K-E_M and E_K-E_L are the difference in energy levels between the K and M shells and K and L shells.
As, E_K-E_M is more than E_K-E_L, λ_α >λ_β. So, (D) is incorrect.