Which of the following three elements have filled outermost shells?_x005F_x000D_

• A. Magnesium (mg), Helium (He), Neon (Ne)
• B. Magnesium (mg), Calcium (ca), Barium (Ba)
• C. Lithium (Li), Sodium (Na), Potassium (K)
• D. Helium (He), Neon(Ne), Argon (Ar)