What does the average atomic mass represent?
a. the average of many measurements of the mass of the element
b. the best guess of what the real atomic mass of the element
would be
c. the sum of the molar masses of each isotope of the element
d. the weighted average of the masses of the isotopes of the
elements

D.

Explanation:

The weighted average of the  masses of the isotopes.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

56 moles of   lieter in chemistry