When Tracy was a young child, she often complained of stomachaches at bedtime.Her parents discovered that if they gave her the "green medicine" she always felt better immediately. The green medicine consisted of water with green food coloring. This is an example of
stress sensitization
the placebo effect
a paradigm shin
selective attention

The correct answer is B. The placebo effect

Explanation:

The term "placebo effect" describes the use of a neutral medicine or fake treatment that might still improve the symptoms of an individual, which the result of the expectations of the individual rather than an active substance in the "medicine". This effect occurs in the case of Tracy because even if the liquid she takes is only water with green food coloring (fake medicine) her symptoms reduced, which is likely connected to her expectations and other psychological elements. Thus, this is an example of the placebo effect.