Which of the Following Statements About Activity-Based Management (ABM) Is/are

Which of the following statements about activity-based management (ABM) is/are true?

A) ABM is concerned with how to effectively and efficiently manage activities and processes to provide value to the final consumer.
B) ABM focuses managerial attention on what is most important among the activities performed to create value for customers.
C) Defining processes and identifying key activities helps management better understand the business and to evaluate whether activities performed add value to the customer.
D) All of the above are true.