Which is the best approach for gaining support for the new IT service?

[answerhappygod]

A CIO is trying to gain funding and executive level support for an enterprise data warehouse. Which is the best approach for gaining support for the new IT service?
OPTIONS

Develop a value stream map detailing how existing IT staff and systems can be leveraged for the new service
Build a proof of concept service and move some customer data into it to demonstrate the value the new service can deliver
Develop an overall IT transformation program that includes new IT investments required and how they work together to create business value
Develop a business case that clearly describes the service, its benefits, why it is needed and the expected return on investment