Which three of the following are ClusterXL member requirements?

Which three of the following are ClusterXL member requirements? 1) same operating systems
2) same Check Point version
3) same appliance model
4) same policy

A.
1, 2, and 4

B.
1, 2, and 3

C.
1, 3, and 4

D.
2, 3, and 4