R1 is internal to area 1, and R2 is internal to area 2. Subnet 10.1.1.0/24 exists in area 2 as
a connected subnet off R2. ABR ABR1 connects area 1 to backbone area 0, and ABR2
connects area 0 to area 2. Which of the following LSAs must R1 use when calculating R1’s
best route for 10.1.1.0/24?

A.
R2’s Type 1 LSA

B.
Subnet 10.1.1.0/24’s Type 2 LSA

C.
ABR1’s Type 1 LSA in area 0

D.
Subnet 10.1.1.0/24’s Type 3 LSA in Area 0

E.
Subnet 10.1.1.0/24’s Type 3 LSA in Area 1

Explanation:
R1, internal to area 1, can use LSAs only in the area 1 LSDB. R2’s Type 1 LSA exists
only in area 2’s LSDB. The Type 2 LSA for subnet 10.1.1.0/24, if one exists, also
only exists in area 2’s LSDB. R1 will use ABR1’s Type 1 LSA in area 1 to calculate the
possible intra-area routes inside area 1, but R1 will use ABR1’s Type 1 LSA in area 1.
Finally, the Type 3 LSA, created for 10.1.1.0/24, and flooded into area 1, is also
needed to calculate the metriC.