The unit for atomic mass is

A. Gram

B. Amu

C. Pound

D. None of the above

The unit of atomic mass is Amu.

(B) is correct option.

Explanation:

Atomic mass:

The mass of a single atom of a chemical element.

An atom made by the proton, electron and neutron.

One atomic mass unit is explained by one by twelve of the mass of a single carbon - twelve atom.

We know that,

Gram is the unit of mass in C. G. S unit.

Amu is the unit of atomic mass.

Pound is the unit of mass in F. P. S units.

Hence, The unit of atomic mass is Amu.

It's measured in Amu, so the answer is B.