38. Which of the following statement about conjugate vaccines is true? (A) Conjugate vaccine is designed to fight against pathogenic bacteria without capsular polysaccharides. (B) Conjugate vaccines rely on linked recognition between T and B cells. (C) The main aim of conjugate vaccine is to elicit species- and type-specific I cell response to the bacteria. (D) Conjugate vaccines that are developed against H. influenzae type b are not successful.