Which statement about mailing lists is true?

Multiple Choice

The normal commission that a list broker pays to a list owner is $10$ percent.

$$Cleaning$$ occurs when a house list and a compiled list are merged into one.

Mail$-$order advertisers are unable to check the validity of a rented list.

The average mailing list changes by more than $40$ percent per year.

Mailing lists should be updated every four years to maintain validity.