An Electron __________ Will Have the Smallest De Broglie Wavelength $\times$

Multiple Choice

An electron __________ will have the smallest de Broglie wavelength.

A) moving at 220 m/s
B) moving at 20 mi/hr
C) moving at 3600 km/s
D) moving at 25% the speed of light
E) moving at 2.998 $\times$ 10⁸ km/hr