Explanation
A functional requirements specification is a document that describes the software and behavioral requirements of an application, such as what features it should have and how it should behave under different scenarios. It can help communicate the expectations and needs of the stakeholders to the development team. A scope statement specification is a document that defines the project scope, objectives, deliverables, assumptions, constraints, and exclusions. It does not describe the software and behavioral requirements of an application. A system requirements specification is a document that describes the technical requirements of an application, such as hardware, software, security, performance, and reliability. It does not describe the software and behavioral requirements of an application. References:
https://trailhead.salesforce.com/en/content/learn/modules/salesforce-business-analyst-certification-prep/requirem

A business analyst assigned to a Service Cloud project should understand the current business processes and document the existing functionality of the customer service department. This will help them identify the gaps, pain points, and opportunities for improvement. Working with Salesforce to purchase the necessary licenses is a task for the project manager or sponsor. Managing existing Salesforce applications and activities is a task for the administrator or developer. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/customer-di
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/business-pro

Explanation
The element that the business analyst should use to help the QA team validate that the product fulfilled the requirements without ambiguity is acceptance criteria. Acceptance criteria are statements that define the conditions that a product or feature must meet in order to be accepted by stakeholders or end users. They can help the QA team test the functionality based on specific scenarios or outcomes, and verify that it meets the expectations or needs of stakeholders or end users. Process maps are diagrams that show how a business process flows from start to end. They can help the QA team understand how a product or feature works in relation to a process, but not how to validate it without ambiguity. User stories are statements that capture a requirement or feature from an end user's perspective. They can help the QA team understand what needs to be done and why it matters, but not how to validate it without ambiguity. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/user-storiesh