单选题 The Dynamic Host Configuration Protocol provides configuration parameters to Internet ______. DHCP consists of two components: a ______ for delivering host-specific conguration parameters from a DHCP server to a host and a mechanism for allocation of network addresses to hosts. DHCP is built on a client-server model, where designated DHCP server hosts allocate network addresses and deliver ______ parameters to dynamically configured hosts. DHCP supports three mechanisms for IP address allocation, In "automatic allocation", DHCP assigns a ______ parameters to dynamically mechanisms for IP address allocation. In "dynamic allocation", DHCP assigns an address to a client for a limited period of time. In "manual allocation", a client"s IP address is assigned by the network ______, and DHCP is used simply to convey the assigned address to the client.