Explanation/Reference:
In an environment where a host with two HBAs (VMware Best Practice) is connected to two fabrics and storage array with two Storage Controllers (EMC VNX, for example) the host will have four paths to a LUN:
2 Controllers x 2 HBAs = 4 paths
If you go to the extreme and configure your XtremIO with eight X-Brick, you have 16 controllers. Again, two HBAs per host and the max number of LUNs you can attach to an ESXi host will be 32... I understand, different OS'es may have different limits than VMware and this logic will not be applicable.
If you have hit the limit of 1024 paths per host (1024 / 4 controllers / 2 HBAs = 128 LUNs) and need to provision more LUNs, the best way will be to re-zone the host to limit the number of X-Bricks / Controllers the host HBA can connect to.
The following diagram displays the logical connection topology for 4 paths.

Incorrect Answers:
D: Eliminate single-initiator to single-target zones.
References: http://vstrong.info/2015/11/18/vmware-host-zoning-for-multi-x-brick-emc-xtremio-storage- array/