Ans : C) The smallest number is represented by all zeros.
In computer system, a floating-point number is represented as S E M, i.e. using Sign bit, Exponent bits and Mantissa bits.
The exponent can be a positive as well as a negative number. So to represent negative number we can use 1's complement or 2's complement. Better choice would be 2's complement.
If we use 2's complement system to represent exponent, then problem will arise while comparing 2 floating point numbers. For example, if exponent of the 2 numbers are negative then for comparing we will have to convert them into positive number.
So to avoid this extra work, excess-N code is used so that all exponent can be represented in positive numbers, starting with 0.