Describe the effects of CHECK(expr) in the CREATE TABLE column constraints a. The values assigned to a column must be unique in every row i. e. no duplicate values across multiple rows b. The Boolean expression must evaluate to true for the insert or update to successfully complete. A DBMS error will result if the Boolean expression evaluates to false c. If a value is not provided for the column in an insert statement, the given default value will be used to assign a value in the new row. d. That only non-null values must be assigned to the column. Attempting to leave a non-null attribute unassigned during an insert or update will result in a DBMS error.