You can't do that on a switch - a switch doesn't copy packets and one of this type can't change L3 destinations (requiring destination NAT).
You could use port mirroring to duplicate egress frames out of a certain port. Then you could run a forwarder on the monitor port that resends the UDP datagrams elsewhere.
Such a forwarding service likely exists already and would be rather trivial to program, but programming and resource recommendations are explicitly off-topic here.
If Host C is connected to the same switch you could alternatively mirror directly to its port and use promiscuous mode (and possibly packet capturing) to receive the UDP datagrams.
Of course, the correct approach to this type of problem would be to use multicast.