Refer to the exhibit. Routers R1 and R2 have established a neighbor relationship and are
exchanging routing information. The network design requires that R1 receive routing
updates from R2, but not advertise any routes to R2. Which configuration command
sequence will successfully accomplish this task?

A.
R1(config)# router eigrp 1
R1(config-router)# passive-interface serial 0

B.
R2(config)# router eigrp 1
R2(config-router)# passive-interface serial 0

C.
R1(config)# access-list 20 deny any
R1(config)# router eigrp 1
R1(config-router)# distribute-list 20 out serial 0

D.
R2(config)# access-list 20 deny any
R2(config)# router eigrp 1
R2(config-router)# distribute-list 20 out serial 0

E.
R1(config)# access-list 20 permit any
R1(config)# router eigrp 1
R1(config-router)# distribute-list 20 in serial 0

F.
R2(config)# access-list 20 permit any
R2(config)# router eigrp 1
R2(config-router)# distribute-list 20 in serial 0

Explanation:
We can not use passive-interface to accomplish thistask because the “passive-interface…”
command (in EIGRP or OSPF) will shut down the neighbor relationship of these two routers
(no hello packets are exchanged). And to filter routing updates we should configure a
distribute list on R1 with an access list that denyall and apply it to the outbound direction so
that R1 can receive but can not send routing updates.