Explanation:

- Ebullient typically describes someone who is lively and enthusiastic, full of happiness and energy.

- Option 1: Consistent means not changing in behavior or action; it's about being steady.

- Option 2: Indifferent means having no particular interest or sympathy; it's about being apathetic or unconcerned.

- Option 3: Full of energy and excitement is the best synonym for ebullient. This phrase captures the sense of joyful enthusiasm and liveliness.

- Option 4: Fantastic can mean great or wonderful, but it doesn't specifically connote the energetic enthusiasm that ebullient does.

Option 3: Full of energy and excitement is the correct answer.