Which Enhanced Interior Gateway Routing Protocol (EIGRP) packet is NOT sent reliably over the network?

A.
Update

B.
Query

C.
Reply

D.
Acknowledgement

Explanation:
Acknowledgement packets are sent unreliably over the network, and there is no guaranteed delivery of
acknowledgement packets between neighboring routers.
Acknowledgement packets are a special type of hello packets that do not contain data and have a non-zero
acknowledgement number. These are sent as a unicast.
Update, Query, and Reply packets use Reliable Transport Protocol (RTP), which ensures guaranteed delivery
of packets between neighboring devices. The RTP mechanism ensures loop-free synchronized network.Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization,
redistribution, stub)

Internetworking Technology Handbook > Enhanced Interior Gateway Routing Protocol (EIGRP)