Sixteen-​year-old Freddy is sitting on a couch holding his binder, his laptop, and his psychology book. He is feeling a lot of stress because there does not seem to be enough time to study all of the chapters. Every time he thinks he has learned a concept, he gets a question wrong. What hormone would most likely be responsible for his feelings?
A. Ghrelin.
B. Leptin.
C. Oxytocin.
D. Cortisol.
E Testosterone.