Which software category helps unify various applications into one interconnected system?

Middleware is the correct choice in this scenario as it serves as a bridge between different applications and systems, enabling them to communicate and work together effectively. Middleware provides a layer of software that facilitates the integration of various applications, allowing them to share data and functionalities seamlessly. This can involve connecting legacy systems with modern applications or integrating software tools that serve different business functions.

Middleware typically includes services like messaging, authentication, and APIs that enable interoperability between disparate software systems. By using middleware, organizations can create a unified system that streamlines processes, improves data accuracy, and enhances overall efficiency. This interconnectedness is essential for enabling digital transformation and achieving a holistic view of operations across different business units.