What should a developer use so that different implementations of the commission calculation can be invoked on the stage change?

Universal Containers (UC) calculates commissions on their Opportunities in different ways based on complex rules that vary depending on the line of business of the Opportunity.

Whenever a new line of business Is added to Salesforce at UC, it is likely that a different calculation will need to be added too. When an Opportunity’s stage is changed to Closed/Won, its commission should be calculated in real time.

What should a developer use so that different implementations of the commission calculation can be invoked on the stage change?
A . A final dass with multiple methods
B. Apex Describe Schema methods
C. An Apex class with @ custom enum
D. An Interface and implementing classes

Answer: C