An electron is moving with an initial velocity $\mathrm{V}={\mathrm{V}}_0\hat{\mathrm{i}}$  and is in a magnetic field $\mathrm{B}={\mathrm{B}}_0\hat{\mathrm{j}}$. Then, its de Broglie wavelength

• A

  renains constant

• B

  increases with time

• C

  decreases with time   

• D

  first increases then decreases