Explanation:

- Option 1: would do

- This suggests a hypothetical situation. It implies you might help if conditions were different. Appropriate for unreal or unlikely scenarios.

- Option 2: will do

- Indicates a direct offer or promise. You’re agreeing to do the project if the person gets groceries. Correct for this context as it involves a clear condition and future action.

- Option 3: will have done

- Refers to an action completed before a specific future time. Not suitable since it doesn’t fit the immediate condition-action sequence here.

- Option 4: would have done

- Used when talking about past hypothetical situations. Implies you're talking about a condition that hasn’t or wouldn’t be met.