which will be the result?

Two directly connected routers, PassGuide-R1 and PassGuide–R2, are both configured for OSPF graceful restart. PassGuide-R2 is able to switch packets in hardware, but PassGuide-R1 is not. If a network administrator logs on to PassGuide-R2 and performs a system reload, which will be the result?

A.
Traffic forwarded from PassGuide-R2 to or through PassGuide–R1 will continue to be forwarded based on the forwarding table state at the time of the reload. OSPF will rsynchronize its local databases after finishing the reload

B.
PassGuide-R2 will continue to forward traffic to PassGuide–R1, but PassGuide–R1 will drop the traffic because its neighbor adjacency with PassGuide-R2 has failed.

C.
PassGuide-R2 will continue forwarding traffic to and through PassGuide-R1, but PassGuide-R1 will drop this traffic because it is not capable of maintaining its forwarding state

D.
All the traffic PassGuide-R2 is forwarding to or through PassGuide-R1 will be dropped while OSPF rebuilds its neighbor adjacency and forwarding tables.

Explanation:
Graceful Restart Router Operation

Graceful Restart Initiation
The restarting router becomes aware that it should start the graceful restart process when the network administrator issues the appropriate command or when an RP reloads and forces and Redundancy Facility (RF) switchover. The length of the grace period can be set by the network administrator or calculated by the OSPF software of the restarting router. In order to prevent the LSAs from the restarting router from aging out, the grace period should no t exceed an LSA refresh time of 1800 seconds.
In preparation for graceful restart, the restarting router must perform the following action before its software can be reloaded: The restarting router must ensure that its forwarding table is updated and will remain in place during the restart. No OSPF shutdown procedures are performed since neighbor routers must act as if the restarting router is still in service.
The OSPF software is reloaded on the router (it undergoes graceful restart).

OSPF Processes During Graceful Restart
After the router has reloaded, it must modify its OSPF processes until it reestablishes full adjacencies with all former fully adjacent OSPF neighbors. During graceful restart, the restarting router modifies its OSPF processes in the following ways:

The restarting router does not originate LSAs with LS types 1, 5, or 7 so that the other routers in the OSPF domain will use the LSAs that the restarting router had originated prior to reloading. The router does not modify or flush any self-originated LSAs.
The restarting router runs its OSPF routing calculations in order to return any OSPF virtual links to operation. However, the restarting router does not install OSPF routes into the system??s forwarding table, and the router relies on the forwarding entries that it had installed prior to undergoing the graceful restart process.
If the restarting router determines that is was the Designated Router on a given segment prior to the graceful restart, it will reelect itself.

Graceful Restart Process Exit
The restarting router exits the graceful restart process when one of the following events occur:

The router has reestablished all adjacencies. The graceful restart was successful.
The router receives an LSA that is inconsistent with an LSA from the same router prior to the graceful restart. The inconsistency can be mean either that the router does not support the graceful restart feature or that the router has terminated its helper mode for some reason. The graceful restart was unsuccessful.
The grace period has expired. The graceful restart was not successful.
Once the restarting router has completed the graceful restart process, it returns to normal OSPF operation, reoriginating LSAs based on the current state of the router and updating its forwarding tables based on current link-state database contents. At this time, it flushes the grace-lsas that it had originated during the initiation of the graceful restart process.