Which deployment option is invalid for Cisco Unified Contact Center Express?

A.
a two-node Cisco Unified Contact Center Express cluster connected to a Cisco Unified Communications Manager cluster

B.
a one-node Cisco Unified Contact Center Express cluster connected to two Cisco Unified Communications Manager clusters

C.
a one-node Cisco Unified Contact Center Express cluster connected to a Cisco Unified Communications Manager Express router

D.
two Cisco Unified Contact Center Express clusters, each with two nodes, connected to the same Cisco Unified Cisco Unified Communications Manager cluster

Explanation: