Detailed Instructions: 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").
Problem:Fact1: measuring the hardness of minerals requires scratching those materials, Fact2: Carbonate minerals, such as malachite, pearl, and rhodochrosite, are damaged by chemical attack., Question: What is required to measure the hardness of a pearl? (A) lamphreys (B) Playing with it (C) Scratching it (D) keratin (E) melanin content (F) potassium (G) magnesium (H) Helping it
Solution:
C