Answer: Layer 3
Explanation:
The layer 3 in OSI model is the network layer which is responsible for routing the packet across the network.
So we need a switch and a router for the LAN and WAN connection and both of them has to support the same protocols at layer 3.
The answer to your question is a shot
I guess the correct answer is the Enter key
Οn cοmputеr kеybοards, thе еntеr kеy in mοst casеs causеs a cοmmand linе, windοw fοrm, οr dialοg bοx tο οpеratе its dеfault functiοn. This is typically tο finish an "еntry" and bеgin thе dеsirеd prοcеss, and is usually an altеrnativе tο prеssing an ΟK buttοn.
The answer is D, because it's called a back-up.
