As shown in the figure, a parabola intersects the X axis at points A and B, and its vertex P moves on the dotted line C-D-E. If the coordinates of points C, D and E are (-1, 4), (3,4) and (3,3 1) respectively, the minimum value of the abscissa of point B is/kloc-.

A 1。 B 2。 c？ 3.d？ 4.

As can be seen from the figure, when the abscissa of point B is 1, the vertex of the parabola is (-1, 4), and the analytical formula of the parabola is: y=a(x+ 1)2+4. If you substitute the coordinates of point B, then:

0=a( 1+ 1)2+4，a=- 1，

That is, when the abscissa of point B takes the minimum value, the analytical formula of parabola is: y =- 1 (x+ 1) 2+4.

When the abscissa of point A takes the maximum value, the vertex of parabola should take (3, 1), then the analytical formula of parabola at this time is: y =-(x-3) 2+1=-x2+6x-8 =-(x-2) (x-4).

∴A(2,0)、B(4,0).

So choose B.