Which of the following bit patterns represents the value - 9 in two's complement notation?

A. 00011010 B. 11110111 C. 10001001 D. 11111011

B. 11110111

Explanation:

Binary representation of number 9 = 00001001

Binary representation of - 9 would involve calculating the twos complement representation of 00001001

First we compute the ones complement of this number by reversing the bits.

00001001 = > 11110110

Next we calculate the twos complement representation by adding 1 to the ones complement.

11110110+1 = 11110111

So the final representation is 11110111.