Which of the following is not a valid Codd's Relational Database rule?

a$.$ The database must support set$-$level inserts, updates, and deletes.

b$.$ Every value in a table is guaranteed to be accessible through a combination of table name, primary key value, and column name.

c$.$ Any view is theoretically updatable.

d$.$ Application programs and ad hoc facilities are logically unaffected when physical access methods or storage structures are changed.