When you code a column list in an INSERT statement, you can omit columns with default values and columns that allow values.

NULL is the correct answer of this question.

Explanation:

The insert statement is used for inserting a column list into the database this statement is an under Data Manipulation language.When we insert any column into the database there is always a null value stored.

         insert into tablename (column data type).

answer(a) occurs after your prediction;