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

A Return on Investment is a single financial metric or calculation showing profitability; it does not constitute a detailed document covering the full range of business impacts and benefits.

Service Level Requirements capture what the customer needs from a service in terms of performance and availability; they do not analyze business impact or justify investment.

A Business Case is specifically structured to present a thorough analysis of the expected business impacts - both positive and negative - along with quantified benefits, costs, and risks. It gives stakeholders the evidence needed to make an informed investment decision, making it the correct document for detailed impact and benefit analysis.

A Service Level Agreement is a negotiated contract between provider and customer defining agreed service targets; it documents commitments, not business impact analysis or investment benefits.