The AS160 multi-area OSPF autonomous network is shown below. Area 1 R4 R3 R2 Area 3 Area 0 Area 2 R1 AS 50 Assume that the following number of routes (aka prefixes) exist in each of the networks: . Area 0: 50 routes backbone Area 1: 100 routes stub area (totally stubby area) Area 2: 100 routes stub area (totally stubby area) Area 3: 100 routes stub area (totally stubby area) AS 50: 250 routes . a) (8%) Complete the entries in the table below: Type of routes Area 0 Routes Area 1 Routes Area 2 Routes Area 3 Routes # of O intra routes # of IA routes # of external routes # of default routes b) (2%) identify the router types (ABR, ASBR) for R1, R2, R3, and R4