There are $12$ Agile Principles to guide the implementation of Agile Project Management $($APM$).$ Which of the following is not one of those $12$ principles?

a$)$ Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.

b$)$ Define all of the requirements up$-$front so that changes are minimized later in the process.

c$)$ Deliver working software frequently, from a couple of weeks to a couple of months.

d$)$ Business people and developers must work together daily throughout the project.