You want to upgrade a cluster with two members to VPN1 NGK The SmartCenter Server and both members are version VPN1/FireWall1 NG FP3, with the latest Hotfix. What is the correct upgrade procedure?

1. Change the version, in the General Properties of the gatewaycluster object
2. Upgrade the SmartCenter Server, and reboot after upgrade
3. Run cpstop on one member, while leaving the other member running. Upgrade one member at a time, and reboot after upgrade
4. Reinstall the Security Policy

A.
3,2,1,4

B.
2,4,3,1

C.
1,3,2,4

D.
2,3,1,4

E.
1,2,3,4