Studies have investigated the consumption of fermented foods such as kimchi, yogurt and the incidence of social anxiety by college students, and found that eating fermented foods can significantly reduce the occurrence of social anxiety symptoms. The possible reason is that fermented foods can promote digestion and absorption and improve the intestines. Probiotics in the environment, promote emotional health by improving digestive function. Which of the following, if true, would most question the above conclusions? ['The incidence of social anxiety is also related to personality, gender, age, etc.', 'Many emotionally healthy college students never eat fermented foods such as kimchi, yogurt.', 'Kimchi consumption and social anxiety incidence among university students in a country.', 'Many students with test anxiety or social anxiety have diarrhea symptoms to varying degrees.']