In the following figure, which router is the DR?

Designated routers (DRs) are only elected on broadcast (multi-access) networks such as a LAN. The router with the highest IP address will become the designated router. Since Router B has IP addresses of 192.168.10.2/30, 192.168.10.5/30, and 192.168.2.1/24, it will become the DR. Router C is on a non-broadcast multi-access (NBMA), and therefore, it will not be elected to be a designated router. Router D and Router E have IP addresses of 192.168.2.2/24 and 192.168.2.3/24, respectively, which are lower than Router B's interfaces.