I'm sorry but this needs more context, hope this helps a little.
When multiple networks are connected together the system is called a Wide Area Network, or WAN for short.
<em>A real address is the physical address in main memory. Though a virtual address is the address of a storage location in virtual memory.</em>
<em>hopes this help (:`</em>
B. Four bits are enough to store the eight directions
The summary of the question is to determine whether 4 bits can store 8 directions or not.
To understand this question properly, the 8 bits will be seen as 8 different characters.
In computer memory, a computer of n bits can store 2^n characters.
In this case:
i.e. 4 bits
This implies that the memory can store up to 16 characters.
Because 16 > 8, then (b) answers the question.
the maximum value from the first line is 20 - 0 = 20
and from the second 20-5 and 20+5 so the maximum is 25