Please choose the correct answer to the question: Which of the following statements best explains why earthquakes occur more frequently in California than in Massachusetts?

Answer1: The rock found in California is igneous, but the rock found in Massachusetts is sedimentary. Answer2: California is located on the boundary of two crustal plates, but Massachusetts is not. Answer3: The rock under California is soft, but the rock under Massachusetts is hard. Answer4: California is located on a continental plate, but Massachusetts is not.

Answer format: answer1/answer2/answer3/answer4