This question examines the understanding of fixed collocations in English. The correct answer is 'play a role' which is a well-known fixed collocation. Option B is incorrect because 'happy with' is not a fixed collocation but a phrase that can be varied. Option C is incorrect because 'make decision' is grammatically correct but not a fixed collocation; 'make a decision' is the correct form. Option D is incorrect because 'go to school' is a common phrase but not a fixed collocation.