Which three EIGRP packet types are valid?

EIGRP uses the following packet types: hello and acknowledgment, update, and query and reply.
Hello packets are multicast for neighbor discovery/recovery and do not require acknowledgment.
An acknowledgment packet is a hello packet that has no data. Acknowledgment packets contain a
nonzero acknowledgment number and always are sent by using a unicast address.
Update packets are used to convey reachability of destinations. When a new neighbor is
discovered, unicast update packets are sent so that the neighbor can build up its topology table. In
other cases, such as a link-cost change, updates are multicast. Updates always are transmitted
reliably.
Query and reply packets are sent when a destination has no feasible successors. Query packets
are always multicast. Reply packets are sent in response to query packets to instruct the originator
not to recompute the route because feasible successors exist. Reply packets are unicast to the
originator of the query. Both query and reply packets are transmitted reliably.
Reference. http://docwiki.cisco.com/wiki/Enhanced_Interior_Gateway_Routing_Protocol