The purpose of this passage is to ______.

A．The incompatible response method is to force child to make unwanted response repeatedly in presence of stimulus until he or she becomes exhausted
B．The threshold method refers to introducing undesired behavior with a response incompatible with the undesired response so they cannot be performed simultaneously
C．The fatigue method means that engaging in the behavior is transformed into avoiding it by introducing the stimulus at full strength so it becomes a cue for not performing it
D．The fatigue method is that in presence of stimulus teachers have child make response incompatible with unwanted response

A．Parents introduce spinach in small bites or mixed with a food that the child enjoys over time so that the child will not refuse to eat it.
B．Teachers introduce academic content in short blocks of time for young children and gradually increase session length but not to where students become frustrated or bored.
C．Paper with wider lines is first used and then paper with narrow lines is introduced step by step to help children learn printing and handwriting.
D．A child might be made to throw toys until it is no longer fun by his parents in order to change his behavior of repeatedly throwing toys.