What action is performed for untagged outgoing labels in an MPLS router?

Convert the incoming MPLS packet to an untagged packet and then do a FIB lookup

Convert the incoming MPLS packet to an untagged packet and then do a RIB lookup.

Convert the untagged packet to a labeled packet and forward it to the next router

Convert the incoming MPLS packet to an IP packet and forward it to the next router.