Which command sequence correctly enables Adapter FEX on Nexus 5000 Series Switches?

Which command sequence correctly enables Adapter FEX on Nexus 5000 Series Switches?
A. switch(config)# install feature-set virtualization switch(config)# feature-set virtualization
B. switch(config)# install feature-set adapter-fex switch(config)# feature-set adapter-fex
C. switch(config)# install feature-set adapter-fex switch(config)# feature-set virtualization
D. switch(config)# install feature-set virtualization switch(config)# feature-set adapter-fex