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").
Q: Fact1: radioactive dating is used to determine the age of fossils, Fact2: Radioactive dating requires the use of a decay curve., Question: What is used to determine the age of fossils? (A) Calcium carbonate (B) dinosaurs (C) a barometer (D) electron microscope (E) a thermometer (F) a decay curve (G) chemical equations (H) Physical weathering
A:
F