Answer
e. electrons transfer completely from one atom to another.
Work Step by Step
An ionic bond is when one atom transfers its electron(s) to another.
A and B are incorrect because the two ions would tend to not bond since like dislikes like. C is incorrect because while ionic bonds tend to form with a cation and anion, the bond doesn't exactly form when the two ions meet. Lastly D is not correct because it is describing a polar covalent bond, not an ionic bond.
