Unification:Group of answer choicesevaluates the program.solves the type constraints.collects all the type declaration.merges multiple algebraic data types.

To answer the question step by step:

1. Unification: This step evaluates the program and checks for any type constraints that need to be resolved.

2. Solving type constraints: The unification process involves solving any type constraints that are present in the program. This ensures that all types are compatible and consistent.

3. Collecting type declarations: During the unification process, the system collects all the type declarations used in the program. This includes any user-defined types or built-in types.

4. Merging multiple algebraic data types: If the program includes multiple algebraic data types, the unification process merges them together. This ensures that all the data types are unified and can be used interchangeably.

By following these steps, the unification process ensures that the program's types are consistent and compatible, allowing for smooth execution and avoiding any type-related errors.