6 Atoms!
Mg = 1 atom.
O = 4 atoms.
A = 1 atom.
Answer: I think it's C
Explanation: I hope this helps (Sorry if it doesn't)
Carbon molar mass=12
carbon mass in the above question =6
mole=number of atoms/6.02x10²³
6/12= number of atoms/6.02x10²³
number of atoms=1/2 x6.02x10²³
number of atoms= 6.02 x10²³/2
number of atoms=3.01x10²³
Well, an element is a substance that cannot be decomposed into a simpler substance by chemical change, so element is the answer you are probably looking for! Hope this helps!