In parts of South America, vitamin-A deficiency is a serious health problem, especially among children. In one region, agriculturists hope to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in betacarotene, which the body converts into vitamin A. The plan has good chances of success, since sweet potato is a staple of the region's diet and agriculture, and the varieties currently grown contain little beta-carotene.

Which of the following, if true, most strongly supports the prediction that the plan will succeed?

• AThere are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.  
• BThe flesh of SPK004 differs from that of the currently cultivated sweet potatoes in color and texture, so traditional foods would look somewhat different when prepared from SPK004.  
• CFor successful cultivation of SPK004, a soil significantly richer in nitrogen is needed than is needed for the varieties of sweet potato currently cultivated in the region.  
• DThere are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.  
• EThe currently cultivated varieties of sweet potato contain no important nutrients that SPK004 lacks.