An Organization Plan on Purchasing a Custom Software Product Developed

An organization plan on purchasing a custom software product developed by a small vendor to support its business model. Which unique consideration should be made part of the contractual agreement potential long-term risks associated with creating this dependency?

A) A source code escrow clause
B) Right to request an independent review of the software source code
C) Due diligence form requesting statements of compliance with security requirements
D) Access to the technical documentation