A senior project manager is working on a project that will allow two servers across the globe to communicate with one another using web-based technology. Part of the project includes working with technology that is outdated, resulting in the need for a vendor with specific expertise. Because the vendor was in high demand, they included a requirement within the awarded contract that the parts provided by the buyer must be available before the start of the vendor’s work. This is an example of which type of dependency?

A. External B. Discretionary C. Mandatory D. Preferential