AMC is the Annual Maintenance Contract. It is also recognized as the annual fee for SAP software assurance and corelated to direct/indirect bug fixes in general

SAP Software is modular, adaptable, and wide ranging. It allows customers to only pay for what they require and determine what solutions based on their needs, how to deploy software, and the license type

Well, this is a tricky question… let’s put it this way, here are some of the major factors that one must consider before taking a decision on which SAP partner one must choose