(1) Which statement below is not true about the network layers abstraction? (a) Break a complex task of communication into smaller pieces. (b) Lower layers hide the implementation details from higher layers (c) Layering prevents malicious attackers from compromising your code. (d) Lower layers can change implementation without affecting upper layers as long as the interface between layers remains the same (2) What is the payload of the link layer? (a) An IP packet (b) An Ethernet frame (c) A TCP transport segment (d) User data Packet switching versus circuit switching, Which of the following is not true? (a) Packet switching is more efficient for traffic that arrives in "bursts. (b) Circuit switching can provide strict quality of service assurance to connections accepted (3) to be served by the network. (c) In packet switching, packets are routed individually, hop-by-hop towards their destination. (d) Packet switching guarantees a share of the link for a particular connection. (4) Transmission delay (a) is the same as RTT (b) is larger when the distance between a sender and a receiver is longer. (c) depends on link rate (d) depends on how full a queue is (5) SMTP is a protocols that (a) a user can use to check, draft, and edit email messages. (b) transfers messages from mail server to a user agent (c) transfers messages from one mail server to another. (d) all of the above