A customer has provided the pSeries technical specialist with details of an HACMP solution that they would like validated. The solution is for two POWER4+ p630 servers directly attached to a FAStT600 storage server as the shared storage. Each system has the following： ？ 2 integrated network ports ？ 2 fibre channel adapter cards ？ 1 power supply and redundant cooling ？ HACMP v5.1 In addition to a second power supply， what further requirements， if any， are needed to validate this solution and ensure no single point of failure？ （）

A. One fibre channel switch
B. Two fibre channel switches
C. Two Ethernet cards
D. Nothing