Which of the following must match for  two directly connected routers running OSPF to establish a neighbor adjacency?（）

Router R1, a branch router, connects to the Internet using DSL. Some traffic flows through a GRE and IPsec tunnel, over the DSL connection, destined for an Enterprise network.
Which of the following answers best describes the router's logic that tells the router, for a given packet, to apply GRE encapsulation to the packet?（）

Router R1, a branch router, connects to the Internet using DSL. Some traffic flows through a GRE and IPsec tunnel, over the DSL connection, and into the core of an Enterprise network. The branch also allows local hosts to communicate directly with public sites in th e Internet over this same DSL connection.
Which of the following answers defines how the branch NAT config avoids performing NAT for the Enterprise directed traffic but does perform NAT for the Internet - directed traffic?（）

Router R1, a branch router, connects to the Internet using DSL. The engineer plans to use a configuration with a dialer interface. The answers list a feature and interface on which the feature could be configured.
Which combinations accurately describe the interface under which a feature will be configured?（）