6. (10 points) Find a Huffman code when (a) Symbols {a,b,c,d,e} have probabilities {21,41,81161, 161,} (b) The symbols {a,b,c,d,e,f} have probabilities {0.14,0.11,0.12,0.06,0.24,0.33. (c) Compute the efficiency of each code. For each part, clearly show the Huffman tree..