Even changes to the contracted work must flow through the scope change control system. 1 is incorrect because the schedule change control system is invoked if there are changes to the schedule. The question does not define if the changes will affect the schedule or not. 2 is incorrect because the cost change control system is invoked if there are changes to the cost. The question does not define if the changes will affect the costs or not. 3 is incorrect because it does not fully answer the question.