Mr Smith Has Harold Wear a Ribbon When He Is

Mr. Smith has Harold wear a ribbon when he is exhibiting appropriate behavior. While Harold is wearing the ribbon, he receives a high density of positive reinforcement from his teachers. However, when Harold is misbehaving, the ribbon is removed, which signifies that reinforcement will be withheld for three minutes. Which form of time-out does this procedure illustrate?

A) planned ignoring plus restraint
B) reduction of response maintenance stimuli
C) contingent observation
D) planned ignoring