An educational institution is interested in storing the details of courses offered and their enrollment by students. The following relation is designed by the database administrator for this objective:$$

CourseEnrollment $($CourseID$,$ CourseName, StudentID, StudentName, CreditHours, Grade$)$

The attribute CreditHours represents the credit hours associated with the course. The Grade represents the grade obtained by the student in that course. There exists many to many mapping cardinality between entity Course and Student.$$

Given this schema, answer the following questions:$$

a$.$ Whether this relational schema belongs to $1$st Normal Form? Justify your answer.