When you add a row for which you have incomplete information to a SQL table, $\_\_\_\_\_.$

a$.$ you use the INSERT command and enter a value of null for the columns without data

b$.$ the DBMS will always reject the new row the first time you execute the command

c$.$ you use the INSERT command and name the columns for which you are entering data

d$.$ you must change the table structure so that all rows are marked as NOT NULL