Answer:
Option C. Each contains 6.02 x 10^23 atoms
Step-by-step explanation:
From Avogadro's hypothesis, 1mole of an element contained 6.02x10^23 atoms.
If this is so, all elements therefore have the same number of atoms present in them.
1 mole of carbon = 12. 01g/mol = 6.02x10^23 atoms.
1 mol of magnesium = 24.3g/mol = 6.02x10^23 atoms.
From the above we can see that 12.01g of carbon and 24.3g magnesium both have 6.02x10^23 atoms.