Which document shows a detailed analysis of business impact and benefits?

Return on Investment is a financial metric or ratio used to measure profitability, not a comprehensive document that covers business impact and qualitative benefits.

Service Level Requirements document what levels of service the customer needs from a provider and do not address business impact justification or benefit analysis.

A Business Case is specifically designed to present a structured, detailed analysis of why a project or investment should be undertaken, covering business impact, expected benefits, costs, risks, and alternatives. It is the primary artifact used by management to evaluate and authorize proposed initiatives. No other standard ITIL document covers this full scope of business justification and benefit analysis.

A Service Level Agreement is a formal contract between a service provider and customer defining agreed service targets and responsibilities, not a justification document for business impact.