Router B1, an internal router in area 1, displays the following output. The only two
ABRs connected to area 1 are performing Type 3 LSA filterinG. Which of the following
answers is true based on the information in the output from B1?
R1# show ip route 10.1.0.0 255.255.0.0 longer-prefixes
! Legend lines omitted for brevity
10.0.0.0/8 is variably subnetted, 17 subnets, 3 masks
O 10.1.2.0/24 [110/658] via 10.10.13.1, 00:00:32, Serial0/0/0.1
O IA 10.1.1.0/24 [110/658] via 10.10.23.2, 00:41:39, Serial0/0/0.2
O IA 10.1.3.0/24 [110/658] via 10.10.23.2, 00:41:39, Serial0/0/0.2

A.
A Type 3 LSA for 10.2.2.0/24 was filtered by both ABRs.

B.
A Type 3 LSA for 10.1.2.0/24 was not filtered by both ABRs.

C.
A Type 3 LSA for 10.1.3.0/24 was not filtered by at least one ABR.

D.
A Type 3 LSA for 10.1.1.0/24 filtered by both ABRs.

Explanation:
The output lists all R1’s routes for subnets within the range of
10.1.0.0–10.1.255.255, whose prefix lengths are longer than /16. One answer lists subnet
10.2.2.0/24, which is not in this range, so the output cannot be used to confirm
nor deny whether the subnet was filtereD. R1’s route for 10.1.2.0/24 is an intra-area
route by virtue of not listing an IA code by the route; Type 3 LSA filtering only filters
Type 3 LSAs, which routers use to calculate interarea routes, so the output tells
us nothing about any filtering of 10.1.2.0/24. The output shows a single interarea
route for 10.1.3.0/24, so at least one ABR has flooded a Type 3 LSA for this route.
Additionally, the output confirms that at least one ABR flooded a type 3 LSA for
10.1.3.0/24, or the output would not show an IA route for 10.1.3.0/24. So, the type 3
LSA for 10.1.3.0/24 was not filtered by both ABRs.