To ensure that "all requirements and designs align to business requirements" is the purpose of...

The purpose of the Validate Requirements task is to ensure that all requirements and designs align to business requirements, meet stakeholder needs, and support the business goals. It focuses on ensuring that the proposed solution addresses the underlying business problem or opportunity.

BABOK® Reference – Task: Validate Requirements (Section 7.6):

“The purpose of Validate Requirements is to ensure that all requirements and designs align to the business requirements and support the delivery of needed value.”