<image>(2006 Hainan) In order to select the corn seeds suitable for a certain area, an agricultural research institute conducted experiments with 10 test fields each for variety A and variety B of sweet corn. They obtained two sets of data on the yield per hectare for these two varieties of sweet corn (as shown in the figure). Based on the information in the figure, it can be determined that the yield of ____ variety of sweet corn is more stable in the test fields.