Final answer:
The best represents the Schachter-Singer two-factor theory, illustrating that both physiological arousal and cognitive appraisal are essential to emotional experience.
Step-by-step explanation:
The equation "stimulus = physiological response + emotion" BEST represents the Schachter-Singer two-factor theory of emotion. According to this theory, emotional experiences are the result of both physiological arousal and a cognitive appraisal of the situation. The physiological response to a stimulus is interpreted within a context, which then produces the emotional experience. Schachter and Singer's landmark study involved injecting participants with epinephrine and observing their emotional reactions either with accurate, misleading, or no information about the injection's side effects, supporting the idea that cognition plays a critical role in emotion.