You are planning to connect your three branch offices to the corporate site via Frame Relay. The first branch office has been assigned the network 10.1.0.0/16, the second 10.2.0.0/16, the third 10.3.0.0/16, and the corporate headquarters uses 10.0.0.0/16. You would like to summarize all branch and corporate networks into a single route at the corporate site. Which network address and subnet mask should you choose?