In my opinion, The answer should be "Collect scope requirements" because without collect scope requirements it cannot be planned how to manage the scope.
Am I right?
Project scope statement is a part of scope baseline which can be done only after defining scope. Collecting the requirement is after the plan is established. So the best answer would be option (2)
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®