Atomic mass is the primary atomic characteristic
that Mendeleev used to organize the periodic table.
The atomic mass (ma) is the mass of an atomic particle,
sub-atomic particle,
or molecule. It is commonly expressed in unified atomic mass units
(u) where by international agreement, 1 unified atomic mass unit is
defined as 1/12 of the mass of a single carbon-12 atom (at rest).
The correct answer between all
the choices given is the first choice or letter A. I am hoping that this answer
has satisfied your query and it will be able to help you in your endeavor, and
if you would like, feel free to ask another question.
