Electrons of mass m with de-Broglie wave length $$\lambda$$ fall on the target in an X-ray tube. The cutoff wavelength $$(\lambda_0)$$ of the emitted X-ray is

A

$$\lambda_0=\frac{2h}{mc}$$

B

$$\lambda_0=\frac{2m^{2}c^2\lambda^2}{h^2}$$

C

$$\lambda_0=\lambda$$

D

$$\lambda_0=\frac{2mc\lambda^2}{h}$$