Answer:b. two-factor
Explanation: according to the two factor theory for us to define an emotion that we feel, we first have to experience a physiological arousal which is then interpreted by our brain to assign emotions.In this case physiological arousal is heart pounding and trembling , after this arousal we are able to assign the emotions that we are actual terrified. This means in our emotions, there are two factors involved physiological arousal then the interpretation by our brain of emotions.