Suppose the letters a, b, c, d, e, f have the probabilities 1/2, 1/4, 1/8, 1/16, 1/32, 1/32 respectively. Which of the following is the Huffman code for the letters a, b, c, d, e, f?

a) 0, 10, 110, 1110, 11110, 11111
b) 0, 01, 10, 110, 1110, 1111
c) 00, 01, 10, 110, 1110, 1111
d) 0, 1, 01, 001, 0001, 0000