Which tasks should a project manager accomplish in order to manage project scope correctly?

Define. Validate, and Control Scope. Control Schedule; Control Costs and Manage Stakeholder Engagement

Collect Requirements. Define Scope. Create WBS. Develop Schedule, and Manage Stakeholder Engagement

Plan Scope Management; Collect Requirements; Define. Validate, and Control Scope; and Create WBS

Define. Validate, and Control Scope. Control Costs. Manage Stakeholder Engagement, and keep budget under control