Which role should be assigned to a user so they can read and retrieve data...

According to the Product Documentation for ServiceNow, the business stakeholder role (rm_business_stakeholder) can read and retrieve data from any table of the Release Management application to generate reports. This role can also view the release dashboard, release calendar, and release roadmap. The other roles have different levels of access and permissions for the Release Management application. You can find more information about the roles and responsibilities for Release Management in the Product Documentation for ServiceNow.