Which three statements about DHCPv4 are true? 1) The DHCPREQUEST message is sent by a DHCP client to locate a DHCP server. 2) The DHCPOFFER message is sent by a DHCP server after receiving a DHCPDISCOVER message from a client. 3) All DHCP communications are broadcast. 4) DHCP uses ports 67 and 68. 5) DHCP messages use UDP as a transport protocol. 6) The DHCPACK message is sent by the DHCP server to provide the DHCP client with the DHCP server MAC address for further communications.