Aperson who wants to buy a compact disc (cd) has just enough money to buy one, and chooses cd a instead of cd
b. what is cd b?

The answer is Opportunity Cost.  To better understand what this question is asking, it is right to explain what opportunity cost is.

Opportunity cost is what you have to give up to get what you want. In this case, Client X has to give up on cd b because he does not have enough money to purchase it and ends up buying cd a. To get the most out of life, we have to be aware of what we are giving up on in order to get something else. Client X has made the choice of buying cd a and forgotten the the other option for now.

solution:

this situation is called an ip conflict.

data from a server is sent in small bits called packets. in an ip conflict, some packets will end up in one computer while some other packets will end up in another computer.

so…overall none of the computers get the data as the original message or picture being sent by the server cannot be retrieved with only half the packets. so it will show up as an error.

thus the final answer is d.