The diagram below illustrates the number of moose (red curve) and wolves (blue curve) between 1960 and 2015 in the Isle Royale National Park (USA). It does not show the actual data, but it approximates the trend. The vertical scale is from 0 to 50 for wolves and 0 to 2500 for moose. In certain years the moose population was decreasing and the wolf population was increasing. Which of the options below represents such a year? A. 1980   B. 1970   C. 2000   D. 2010