Which two elements of financial management for IT services are mandatory?

Charging is an optional sub-process in ITIL financial management, not a mandatory one, making this pairing with budgeting incorrect.

Charging is optional, not mandatory, making this pairing with accounting incorrect regardless of accounting's mandatory status.

ITIL Financial Management consists of three sub-processes: budgeting, accounting, and charging. Budgeting - which involves planning future IT expenditure - and accounting - which tracks and allocates actual IT costs - are mandatory for all organizations managing IT finances. Charging, which involves billing internal business units or external customers for IT services, is optional and only relevant to organizations that operate as profit centers or need formal cost recovery.

Costing is an activity within the accounting sub-process rather than a separate mandatory element, and charging remains optional, so this pair does not represent the two mandatory components.