Fred's dog was classically conditioned to salivate at the sound of a bell. fred then repeatedly paired the bell with another stimulus, a whistle. now whenever he blows the whistle, his dog salivates, even though the whistle has never been paired with food. this example illustrates:
a. higher order conditioning (second-order conditioning).
b. spontaneous recovery.
c. a placebo response.
d. biological preparedness.

Higher-order conditioning (second-order conditioning)

Explanation:  

Higher-order conditioning (second-order conditioning) is not about the direct threaten of stimulus but it is about the indirect threaten of the stimulus. It involves disturbances in emotional and behavioral stimuli. This type of conditioning occurs with the people who faced any type of trauma in their life.

It occurs with the pairing of the situation with the traumatic situation. This conditioning includes negative emotions as well as less or neutral cues related to the situation. Thus the neutral cue creates the same disturbance as happened in the original situation.  

Thus here in the above context, Fred's dog was conditioned at the sound of the bell for salvation. After that Fred associated the bell with another stimulus like a whistling sound.

Fred's dog even then salivate when it hears the sound of the whistle, he never heard before. This illustrates the second-order conditioning or higher-order conditioning.  

option c

explanation:

strive for superiority

answer; continous;