An ISP runs OSPF with a backbone (area 0) and a customer aggregation area (area 20) that contains dozens of /30 point-to-point loopback and link networks in the 10.20.0.0/16 range. You want the ABR to advertise only a single 10.20.0.0/16 Type 3 summary into area 0 to reduce LSDB size and improve convergence. Which configuration on the ABR achieves this correctly?