What Happens to the De Broglie Wavelength of an Electron

Multiple Choice

What happens to the de Broglie wavelength of an electron if its momentum is reduced to one-half of its initial value?

A) The wavelength decreases by a factor of 4.
B) The wavelength increases by a factor of 4.
C) The wavelength increases by a factor of 3.
D) The wavelength increases by a factor of 2.
E) The wavelength decreases by a factor of 2.