The figure below shows $3$ Ethernet subnets each with a link$-$layer switch $(S_1,S_2,S_3).$ The subnets are

interconnected by Router R$.$ The IP and MAC addresses of various interfaces $($for each host and the router$)$ are

indicated in the figure. The MAC addresses are indicated in a simplified format using letters. Assume that the

forwarding tables at all hosts and the router $R$ are correctly configured.

Initially the ARP tables for all interfaces are empty. You may assume that any ARP replies received by an interface

will be cached $($i$.$e$.,$ can be used, if relevant, for subsequent questions$).$ There is no other traffic exchanged in the

network other than that specified in the questions below.

Answer the following three questions. Each question is worth $1$ mark.

$(1)$ The host $10\mathrm{.}2\mathrm{.}0\mathrm{.}1$ sends a message to host $10\mathrm{.}2\mathrm{.}0\mathrm{.}2.$ Specify the MAC addresses of all the host and$/$or router

interfaces $($if any$)$ that will receive an ARP request packet before the message can be sent.

$(2)$ Next, the host $10\mathrm{.}2\mathrm{.}0\mathrm{.}3$ sends a message to host $10\mathrm{.}2\mathrm{.}0\mathrm{.}2.$ Specify the MAC addresses of all the host and$/$or

router interfaces $($if any$)$ that will receive an ARP request packet before the message can be sent.

$(3)$ Finally, the host $10\mathrm{.}2\mathrm{.}0\mathrm{.}1$ wants to send a message to host $10\mathrm{.}0\mathrm{.}0\mathrm{.}2.$ After all the appropriate ARP queries and

replies occur, what destination MAC address should the sending adapter on $10\mathrm{.}2\mathrm{.}0\mathrm{.}1$ insert into the Ethernet

frame header that encapsulates the message being sent to $10\mathrm{.}0\mathrm{.}0\mathrm{.}2?$