Question

One electron has a mass of

A. 1 amu
B. 2 amu
C. 0 amu
D. 3 amu

Answer 1

Expressed in terms of "Atomic Mass Units, the electron's mass is
about 0.00054 .  That is, it takes about 1,840 electrons to add up to
1 AMU of mass.

Choice-C on the list is not exactly true, but it's a lot closer than any
of the others.