What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0?

• A. None of these
• B. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
• C. ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0);
• D. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0);

Answer: (B)