A financial analyst is evaluating a complex investment model that includes multiple variables such as interest rates, market volatility, and economic growth. The analyst wants to understand how these factors interact and affect the model's output under various future economic conditions. Which combination of risk analysis techniques would be most appropriate and comprehensive for this task?

Select one:

a$.$ Multi$-$variable sensitivity analysis and worst$-$case scenario analysis

b$.$ One$-$variable sensitivity analysis followed by stress testing with extreme value tests

c$.$ One$-$variable sensitivity analysis and best$-$case scenario analysis

d$.$ Multi$-$variable sensitivity analysis followed by scenario analysis encompassing best$-$case, worst$-$case, and expected scenarios