Given the task definition and input, reply with output. In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Cells secrete acids and bases to maintain the proper pH for enzymes to work., Fact2: Enzyme mechanisms Enzymes are biological catalysts., Question: For biological catalysts to maintain proper pH, what is needed to maintain proper pH? (A) Fully cooking the oysters (B) raising their temperature (C) Organic compounds (D) Something made from fermented ricce (E) metabolic reaction (F) Chemical energy (G) Something coming from a gland (H) secretion of acids and bases
H