To assign a value to a field based on another field's value calculation in SAP Service Cloud V2, a determination is used. Determinations are rules that automatically calculate and set field values based on predefined conditions or calculations. According to SAP documentation, 'Determinations are used to calculate and assign field values dynamically based on other field values or conditions.'

A workflow (A) manages process flows, not field calculations. A field attribute (B) defines field properties, not calculations. An autoflow (D) automates actions but is not used for field value calculations.

SAP Help Portal: Determination Rules in SAP Service Cloud V2

SAP Community: Field Value Calculations