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