If a neutral aluminum atom (al, Z = 13) becomes al + ¹³ it means that this A) lost 1 electron
B) lost 3 electrons
C) gained 1 electron
D) gained 3 electrons

B) lost 3 electrons

Explanation:

I assume you mean Al⁺³.  That means the atom loses 3 electrons.  Electrons have a negative charge, so losing them gives the ion an overall positive charge.

reserve is the answer