The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which or tile following is true about antigenic drift?   (A) It is seen only in influenza virus type A   (B) It is a result of framesshift mutation   (C) It mostly affects the matrix protein   (D) It mostly affects the matrix protein
['(D) It mostly affects the matrix protein <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) It is seen only in influenza virus type A \n (B) It is a result of framesshift mutation \n (C) It mostly affects the matrix protein \n (D) It mostly affects the matrix protein <> possible answers', '  Which or tile following is true about antigenic drift? <> context@']