The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which of the following is the function of Hyperpolarizing Cyclic Nucleotide (HCN) gated channels?   (A) Cardiac rhythm generation   (B) Generation of mitochondrial action potential   (C) Myocardial muscle contraction   (D) Memory formation
['(A) Cardiac rhythm generation <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Cardiac rhythm generation \n (B) Generation of mitochondrial action potential \n (C) Myocardial muscle contraction \n (D) Memory formation <> possible answers', '  Which of the following is the function of Hyperpolarizing Cyclic Nucleotide (HCN) gated channels? <> context@']