Choose the option which is grammatically correct:

The correct answer is Option (2) → She is wise enough to decide on the right course of action.

Position of "enough":

• With an adjective or adverb, enough comes after it: adjective + enough + to-infinitive (wise enough to decide).
• With a noun, enough comes before it: enough money, enough time.
• This sentence: "wise" is an adjective, so the correct order is "wise enough to decide": her wisdom is sufficient for making the right choice.
• Complete sentence: She is wise enough to decide on the right course of action.

Why the Other Options are Incorrect?

Option 1: She is enough wise to decide on the right course of action. — Incorrect. Enough is placed before the adjective. It must follow it: "wise enough".

Option 3: She is too wise to decide on the right course of action. — Incorrect. Too + adjective + to-infinitive means the quality is so great that the action becomes impossible. It would say that her wisdom stops her from deciding, which makes no sense.
Example: The box is too heavy to lift.

Option 4: She is wise rather to decide on the right course of action. — Incorrect. Rather comes before an adjective (rather wise) and does not form the "adjective + to-infinitive" pattern. The sentence has no clear meaning.

Contrast: "wise enough to decide" means wise to the degree needed, so she can decide. "Too wise to decide" would mean so wise that she cannot decide.