Based on this cell from the periodic table, which statement is true for the element magnesium?

A. A magnesium atom contains 12 protons, and neutral magnesium
atoms contain 24 electrons.
B. A magnesium atom contains 12 protons, and most magnesium
atoms contain 12 neutrons.
C. The atomic number of magnesium is 24.3, and its atomic mass is
12
D. The atomic number of magnesium is 12, and its average atomic
mass is 12