In substitution type of questions, some particular objects are assigned code names. Then a question is asked that is to be answered in the code language.
If rat is called dog, dog is called mongoose, mangoose is called lion, lion is called snake and snake is called elephant, which is reared as pet ?
Clearly, 'dog' is reared as pet.
But 'dog' is called 'mangoose'.
So, a 'mangoose' is reared as pet.