Doctor: Medication to reduce blood pressure often has unhealthy side effects. However, lifestyle changes such as exercising more and avoiding fatty foods reduce blood pressure just as effectively as taking medication does. Ttherefore, it is healthier to rely on these lifestyle changes than on medication to reduce blood pressure. Which one of the following is an assumption that the doctor's argument requires? ['Other than medication, the only way to reduce blood pressure is by making lifestyle changes such as exercising more and avoiding fatty foods.', 'The side effects, if any, of exercising more and avoiding fatty foods in order to reduce blood pressure are less unhealthy than those of taking medication to reduce blood pressure.', 'If it is healthier to rely on a lifestyle change than on medication to reduce blood pressure, then that lifestyle change reduces blood pressure at least as effectively as medication does.', 'If an alternative to medication relieves a medical condition just as effectively as medication does, then it is always healthier to rely on that alternative than on medication to relieve that medical condition.']