Alright, so Nishi is taking an important exam and she feels very nervous about it. She notices that her heart rate is elevated and her palms are sweating. These responses reflect which component of emotion. So remember, emotion has 3 main components: physiology, cognition, and behavior.
The changes being described here, her higher heart rate and sweaty palms, are reflecting some physiological changes. Right? Something changing in her biology because of the emotion that she is experiencing. Now, if we're thinking about these other components, the fact that she is aware of being nervous reflects the cognitive aspect of emotion, which is her subjective feeling and understanding of what is happening in her body. And then behavioral would include any facial expressions, body posture, things like that that signal to other people what emotion you might be feeling.
And then remember, mood is a completely separate thing from emotion. Moods tend to be more diffuse, they are longer lasting, and they tend to be lower intensity. Alright, so our answer here is A; this is a physiological component of emotion. And there you go.