According to paragraph 4, what happened when geologists at the turn of the twentieth century tried to estimate Earth's age? A. They ignored Hutton's findings about rates of sedimentation and thus tended to underestimate the age by a factor of 10 to 50. B. Using the sedimentary record, they were able to guess the correct age within 100 million to 400 million years. C. They did not realize that much of the sedimentary record is missing and thus assumed that Earth is much younger than it actually is. D. They did not correctly calculate the rates of sedimentation and thus concluded that Earth is much older than it actually is.