Explanation:

- Option 1: Eligible generally means someone or something that is suitable or worthy of being chosen or for a privilege. This relates more to qualifications rather than consumption.

- Option 2: Digestible refers to something, often food, that can be broken down in the body. While related to food, it does not indicate whether something is fit to eat.

- Option 3: Curable means something that can be healed or remedied, like a disease. It doesn't relate to food or consumption.

- Option 4: Edible means something that is safe and suitable for eating. It perfectly describes a thing fit to eat.

Edible is the correct choice.