According to the passage, scientists are able to discover weathered material on the Martian surface because they have benefited from which of the following? A. a new method to analyze volcanic craters created on the Martian surface. B. an improved ability to detect hydrated materials on the Martian surface. C. a more sophisticated understanding of the effect of wind-borne dust on the Martian surface. D. a decision to look for water primarily in heavily cratered highland regions. E. a better understanding of how erosion might affect clay deposits.