Rollout planning can go wrong if the wrong programs get modernised first. What should discovery establish before any transformation work starts?

The correct answer is the option that says discovery should establish the application's dependencies, data flows, transactions, and which parts form sensible candidate boundaries for modernisation. Discovery exists to surface what actually depends on what, how data moves through the system, where transaction boundaries fall, and therefore where the system can be safely divided for modernisation. The option saying discovery is optional once the team is confident in its own knowledge of the code is incorrect because assumed knowledge of a decades-old mainframe estate is exactly what discovery is meant to test and correct. The option saying only a list of file names is enough is incorrect because file names frequently do not match what a program actually does, and relying on them skips the analysis discovery provides. The option saying to start with the physically smallest programs is incorrect because size alone says nothing about dependencies or business importance. For the exam, tie discovery output to dependencies, data flows, transactions and modernisation boundaries.