## Answer & Solution

Answer:** Option A**

Solution:

An integer is a number with no fractional part; it can be positive, negative or zero. In ordinary usage, one uses a minus sign to designate a negative integer. However, a computer can only store information in bits, which can only have the values zero or one. We might expect, therefore, that the storage of negative integers in a computer might require some special technique. As you might imagine, an unsigned integer is either positive or zero.
Consider a single digit decimal number: In a single decimal digit, you can write a number between 0 and 9. In two decimal digits, you can write a number between 0 and 99, and so on.
Since nine is equivalent to 10

^{1} - 1,
99 is equivalent to 10

^{2} - 1, etc.
In n decimal digits, you can write a number between 0 and 10

^{n} - 1.
So, analogously, in the binary number system,
An unsigned integer containing n bits can have a value between 0 and 2

^{n} - 1
(which is 2

^{n} different values).