Comprehensive and Detailed in Depth Explanation:
To pay employees in three business units from different bank accounts in Oracle Payroll Cloud, you need: (1) "Create three organization payment methods each with a different payment source" (A) to define distinct bank accounts; (2) "Write a formula to retrieve the employees' business unit details" (C) to dynamically assign payment methods based on business unit; and (3) "Create one organization payment method with three payment sources and define three payment method rules based on each business unit" (D) to link the payment sources to business units via rules. Option B (Default Payer Element) is unrelated to this requirement. This is detailed in the "Payment Methods Setup" section.