Students (studentid, firstName, lastName, email) Professors (professorld, firstName, lastName, email) Courses (courseld, course Title, description, professorld) (NOTE: professorld is a foreign key. Each course is being taught by only one professor) Grades (studentid, courseld, score, offering) (NOTE: score is a number from 1 to 100. Offering is a string used to identify when a course was offered, for example "Sep2019" means the course was offered in September 2019) Formulate the following SQL Statements: a. Write the DDL to create the table Courses. 5 points b. Write a query that for each professor will print the id, firstName, lastName, email and the number of courses offered by that professor. 5 points C. Write a SQL query which will add a new column named 'GPA score' to the table Students. 5 points d. List the emails of students which have ALL their scores less than 75. The emails should be printed only once. If a student does not have any grades, their email should NOT be printed. 10 points e. Write a query which will list the email of the professor(s) who teach(es) the course in which the biggest number of students in the same offering got a score below 50.15 points