Which design consideration is valid when you contrast fabricPath and trill?

Both FabricPath and TRILL use IS-IS as their control plane routing protocol; VxLAN is a separate overlay encapsulation technology unrelated to TRILL's design.

Both FabricPath (Cisco's proprietary TRILL-based implementation) and standard TRILL support active-active FHRP, enabling all gateway devices to actively forward traffic simultaneously without STP-blocked ports. This active-active capability is a fundamental design advantage shared by both technologies and is a key reason enterprises deploy them over traditional spanning tree architectures.

Both FabricPath and TRILL support ECMP (Equal Cost Multi-Path) forwarding; neither technology restricts traffic to a single path as traditional STP does.

TRILL also supports active-active forwarding mode and is not limited to active-standby operation, so this statement incorrectly characterizes TRILL's capabilities.