input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** HCO3/H2CO3 is the best buffer because it is:   (A) pKa near physiological pH   (B) Its components can be increased or decreased in the body as needed   (C) Good acceptor and donor of H+ ions   (D) Combination of a weak acid and weak base
output: ['(B) Its components can be increased or decreased in the body as needed <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) pKa near physiological pH  (B) Its components can be increased or decreased in the body as needed  (C) Good acceptor and donor of H+ ions  (D) Combination of a weak acid and weak base <> possible answers', '  HCO3/H2CO3 is the best buffer because it is: <> context']