True or False: State if the following claims are True or False and explain your reasoning. a. The third layer of the network stack is the transport layer. b. Layering in the network stack is an example of the end-to-end principle. c. We implement all the same layers in both the host and routers. d. The operating system (OS) supports logical ports while a router only has physical ports. e. Layers 4 and 7 are used for forwarding in switches/ routers. f. On-demand circuit-switching is adopted by the Internet