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 cook is called butler, butler is called manager, manager is called teacher, teacher is called clerk and clerk is called principal, who will teach in a class ?
Clearly, a 'teacher' teachs in a class and as given 'teacher' is called 'clerk'.
So, a 'clerk' will teach in the class.
Hence, the answer is (e).