B. DHCP ACK

Here’s a brief overview of each DHCP message type:

DHCP DISCOVER: Sent by the client to discover available DHCP servers.
DHCP OFFER: Sent by the DHCP server to offer an IP address and other configuration parameters to the client.
DHCP REQUEST: Sent by the client to request the offered IP address and to accept the parameters offered by the DHCP server.
DHCP ACK: Sent by the DHCP server to confirm that the client can use the IP address and the configuration parameters.
Thus, the correct message for confirming that the host can use the IP address is DHCP ACK