When the plane parallel to the bottom of the cone is used to cut the cone, the ratio of the area of the cross section to the area of the bottom is 1:3. The ratio of the two sections which divide the generatrix of the cone into two sections is () A. 1：3B. 1：（3-1）C. 1：9D. 3：2

When the plane parallel to the bottom of the cone is used to cut the cone, the ratio of the area of the cross section to the area of the bottom is 1:3. The ratio of the two sections which divide the generatrix of the cone into two sections is () A. 1：3B. 1：（3-1）C. 1：9D. 3：2

The plane parallel to the bottom of the cone is used to cut the cone. The truncated small cone is similar to the large cone. The ratio of the cross-sectional area to the bottom area is 1:3, so the similarity ratio of the small cone and the large cone is 1:3, so the generatrix length ratio of the small cone and the large cone is 1:3, so the generatrix length ratio of the small cone and the frustum is 1: (3-1), so B is selected