Which key difference between these products should the storage specialist discuss with the customer?

A customer is looking for two new SAN Switches. A Business Partner suggested the Cisco MDS 9148 or IBM SAN48B-5.

Which key difference between these products should the storage specialist discuss with the customer?
A . Cisco MDS 9148 supports FICON attachment
B . IBM SAN48B-5 switches offer "ports on demand" scalability
C . Cisco MDS 9148 supports USB for microcode upgradability
D . IBM SAN48B-5 supports optional 16 Gbps SFP+ connections

Answer: D