What link aggregation technology could be used when configuring port-channels for connecting an access switch to vPC Domain?

Dot1q is a VLAN tagging standard and not a link aggregation technology used for forming port-channels.

'LACP mode on' is not a standard LACP configuration mode; LACP typically uses 'active' or 'passive' modes for negotiation.

PAgP (Port Aggregation Protocol) is a Cisco proprietary link aggregation protocol that is not supported or recommended for vPC deployments, which strictly require LACP.

For vPC (Virtual Port-Channel) domains in Cisco Nexus environments, LACP (Link Aggregation Control Protocol) is the mandatory protocol for bundling links into port-channels. Specifically, configuring LACP in 'active' mode on the access switch side ensures it actively negotiates with the vPC peers, properly forming the port-channel and enabling load balancing and failover.

'Nonegotiate mode' or EtherChannel without negotiation is not compatible with vPC, as vPC relies on LACP negotiation to manage the multi-chassis EtherChannel.