$5.[$Linker Layer Addressing, $\backslash (\backslash$mathbf$\{15\}\backslash )$ pt$]$ Consider the network diagram below. The IP and MAC addresses are shown for nodes $\backslash ($ A$,$ B$,$ C $\backslash )$ and $\backslash ($ D $\backslash ),$ as well as for the router's interfaces.

Consider an IP datagram being sent from node A to node C$.$ Answer the following questions:

a$.$ What are the source MAC address and destination MAC address at point $1?$

b$.$ What are the source IP address and destination IP address at point $1?$

c$.$ Do the source and destination MAC addresses change at point $2?($Yes or no$.$ If yes, indicate the new addresses.$)$

d$.$ Do the source and destination MAC addresses change at point $4?($Yes or no$.$ If yes, indicate the new addresses.$)$

e$.$ Do the source and destination MAC addresses change at point $6?($Yes or no$.$ If yes, indicate the new addresses.$)$