is the project manager is the answer, generally scope is defined by the sponsor

BABOK v3 6.4.7 states Project Manager is responsible for managing change and planning the detailed activities to complete a change. In a project, the project manager is responsible for the project scope, which covers all the work to be performed by the project team.

I'll go for C Project Scope: Project Scope includes all the work that needs to be done to create a product, or deliver a service or result. Project Scope is all about the project; it defines the work required to create and deploy the product. The project manager prepares the project scope statement. Solution Scope: The Product or Solution Scope is the characteristics, features, or function of the product or service that is to be built. Solution scope is all about the solution to be implemented: how will it look like, how will it function, and other characteristics, etc. A business analyst prepares the product or solution scope.

Option B Babok v2 page 67

A: pg 98

I think it's A. This is what Babok V3 (2.4.7, 2.4.9) says Project managers are responsible for managing the work required to deliver a a solution that meets a business need, and for ensuring that the project's objectives are met while balancing the project factors including scope, budget, schedule, resources, quality, and risk. Sponsors authorize the work to be performed, and control the budget and scope for the initiative.

PROJECT MANAGER

Project Manager: responsible for managing change and planning the detailed activities to complete a change. In a project, the project manager is responsible for the project scope, which covers all the work to be performed by the project team. BABOk v3. p. 131