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: a seismometer is used to measure the strength or magnitude of an earthquake, Fact2: Earthquakes are measured on a scale of 1 to 10., Question: How do we grade earthquakes (A) Seisometers (B) Cladistics (C) feedback (D) Measuring the ground (E) Check out the sky (F) classified (G) Taking temperature (H) the Himalayas
A:
A