A primary school is managed by a headmaster who in turn is in charge of the teachers and the pupils. A parent brings a child to school and pays school fees to such a child. A teacher is usually on duty from time to time. A teacher on duty has special responsibility of ensuring the students follow rules throughout the day at school. A pupil is identified by their name, ID, grade, and parent. A parent may either be the father of the pupil or the mother. A pupil goes to class where he or she is attended to by the teachers through teaching. Every teacher attends a lesson according to the schedule provided on the timetable. Draw an Entity Relationship Diagram for the scenario above.