In a certain code, 'RAT' is coded as '789', 'BAT' as '456', and 'CAT' as '123'. What is the code for 'TAB'?

Answer: C. 456
The letters in 'TAB' correspond to the code for 'BAT', where 'T' is the 4th letter, 'A' the 5th, and 'B' the 6th.