Final answer:
The 'Posted' or 'Billed' status of a Bill Segment updates the Financial Transaction in a customer's balance, which is vital in the accounting cycle to reflect current charges.
Step-by-step explanation:
The Bill Segment status that causes the Financial Transaction to be reflected in the customer's balance is typically "Posted" or "Billed". Once a bill segment is in this status, the associated financial transaction is considered complete and the amount due is then updated in the customer's account balance. This is a critical part of the accounting cycle and ensures that the revenue is recognized and the customer's statement reflects the most current charges.