In a mixed number coding system, if 'HELLO' is coded as 8, 12, 15, 18, 21, and 'WORLD' is coded as 23, 15, 18, 12, 4, what is the code for 'GOOD'?

Answer: A. 7, 15, 15, 4
The coding follows a consistent pattern based on the position of letters in the alphabet.