According to the passage, which of the following is true of the rock fragments contained in the sediments studied by Bond? A. The majority of them are composed of red sandstone. B. They must have reached their present location over 1,500 years ago. C. They were carried by icebergs to their present location. D. Most of them were carried to their present location during a warm period in Earth's climatic history. E. They are unlikely to have been carried to their present location during the Little Ice Age.