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 the class?

Explanation

The occupation names are shifted one step. A cook is called a butler, a butler is called a manager, a manager is called a teacher, a teacher is called a clerk, and a clerk is called a principal. Therefore, the actual teacher is called "clerk".