If the code for 'CAT' is 12, 15, 18 and the code for 'DOG' is 14, 17, 20, what is the code for 'BIRD'?

Answer: B. 11, 13, 15, 17
The pattern shows an increase in the code values for each subsequent letter. Following the same pattern, 'BIRD' corresponds to 11, 13, 15, 17.