When clients on a different VLAN cannot receive DHCP addresses, it's often because there is noDHCP helper addressconfigured on the router or switch. ADHCP relay/helper addressforwards DHCP requests from clients on the VLAN to the DHCP server, which may reside on a different network. * Confirming the network has a helper address (Answer C):This should be the first step to ensure that DHCP requests from the VLAN are correctly routed to the DHCP server. * Checking client NIC speed (Option A):While important, incorrect NIC speed wouldn't affect the ability to obtain an IP address from DHCP. * Checking NTP server (Option B):Time synchronization is unrelated to DHCP issues. * Authorizing the DHCP server (Option D):This is essential for DHCP operation, but since this is an existing DHCP cluster, the helper address is more likely the issue. CompTIA Server+ Reference:This topic is related toSK0-005 Objective 1.2: Manage server network connections.