The best approach to assist an enterprise in planning for IT-enabled investments is enterprise architecture (EA). EA is a holistic and integrated view of the current and future state of the business, IT, and their alignment1. EA helps to identify and prioritize the business needs andobjectives, and to design and deliver the IT solutions that support them2. EA also helps to optimize the IT resources and processes, and to ensure that they are aligned with the business strategy and goals3. EA also helps to measure and monitor the IT performance and outcomes, and to evaluate the value and benefits of the IT investments4. EA also helps to manage the risks, costs, and complexity of the IT investments, and to ensure that they comply with the legal and regulatory requirements5.

IT process mapping, task management, and service level management are not as comprehensive or effective as EA in assisting an enterprise in planning for IT-enabled investments. IT process mapping is a visual representation of a process that shows the steps and their relationships6. It can help to understand how a process works, but it does not provide a strategic or architectural view of the business or IT. Task management is a process of managing individual or group tasks to achieve goals7. It can help to track and delegate work, but it does not address the alignment or optimization of IT with the business. Service level management is a process of defining, documenting, and agreeing on service levels within an IT service management system8. It can help to ensure that services are delivered at an agreed level, but it does not cover the design or delivery of IT solutions that meet the business needs. Therefore, EA is the best approach to assist an enterprise in planning for IT-enabled investments.