A Mother Has Been Continually Nagging Her Daughter About How

Multiple Choice

A mother has been continually nagging her daughter about how messy her room is.Finally,the daughter gets so tired of her mom's complaints that she cleans her room,thus stopping the nagging of her mother.Given the fact that the withdrawal of the mother's nagging served to strengthen the daughter's room-cleaning behaviour,the mother's nagging would be considered a(n) :

A) negative reinforcer.
B) positive reinforcer.
C) positive punishment.
D) negative punishment.