This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Which among the following is not true regarding diphtheria carriers? 
Select and explain. 
A. Immunization prevents carrier state, B. Nasal carriers are not dangerous, C. Treatment of contacts is necessary, D. They are responsible for the transmission of the disease.
A: Immunization prevents carrier state
Answer: A: Immunization prevents carrier state 
Explanation: Immunization doesn't prevent carrier state. It only prevents infection. Human carriers are the main reservoir of infection. Infected patients and asymptomatic carriers can transmit C diphtheria respiratory droplets, nasopharyngeal secretions, and rarely fomites. The greatest propoion of carriers is in the age group 1 to 5 years, and owing to the small size and anatomical complexities of the nasal passages, the pathological conditions tend to persist and make examination and treatment difficult. Treatment of contacts is necessary.