1. Give reasonable interpretations of the phrase “minimize the waiting times” in the informally stated requirements of the elevator system. Formalize the chosen interpretations as selection functions to be attached to a Pb1 schema of the type of Check whether your policy still guarantees that all requests will eventually be served. 2. Suppose that your ER language does not support attributes associated with relations, but does support nary relations. Following the discussion in how would you rep-resent the students' proficiency levels in a given class?