1. a. [4 marks] In an OSPF architecture, a network can belong to only one area. Briefly explain the rationale behind this design decision. [150-200 Words] b. [6 marks] When designing the OSPF routing protocol, the designers had the following choices with respect to the placement of this protocol within the protocol stack: i. Option 1: Place the OSPF protocol above the transport layer: OSPF packets are transported over either TCP or UDP segments. ii. Option 2: Place the OSPF protocol directly above the IP layer: OSPF packets are transported over IP datagrams. Option 3: Place the OSPF protocol directly above the data link layer: OSPF packets are transported over data link layer frames. The designers opted for option 2. Briefly explain the rationale behind this design decision. In your answer, briefly highlight the potential drawbacks of using the other two options. [300-350 Words]