Which strategy best reduces data coupling between two COBOL programs that both directly access a shared VSAM file?

Think of it like working hands-on with IBM mainframe systems — the answer here is 'Introducing a data access service that owns the VSAM file and exposes it only through a defined API'. Introducing a data access service that owns the shared file and exposes it through an API decouples the two programs from the file implementation, enabling each to be modernized independently. On real mainframe exams, this concept comes up repeatedly so make sure you have it locked in.