Answer:
B and C.
Step-by-step explanation:
Routers can be defined as a device that routes the data from LAN to other connections.
If a post office delivery mail look exactly like the routers then message delivery will look like the mailman will use different paths to deliver letter to your home. Each time the mailman will sometimes use different paths to do so.
Another similarity shared between the router and post office delivery will be that the letters will be written on the outside of the envelope instead of inside the envelopes.
Therefore, the correct options are B and C.