A research paper published in a famous foreign academic journal reveals that when people are angry, there will be a series of reactions in the body, which will make the heart beat faster and endocrine disorder, and cause high blood pressure and digestive system disorder. In severe cases, it may cause vomiting or even fainting, and it can also cause skin freckles to increase in the future. Zhang San hopes that his child can go to a famous university. If he sees the grades his child are not satisfactory, he will sulk.
The statement 'In the final exam of the semester, the grades of two of the son of the Zhang San subjects dropped' can best lead to the conclusion that Zhang San is angry based on the conclusion of the question.