Describe a cross section formed by a vertical plane that intersects the front face and the vertex of the pyramid shown. The figure is not drawn to scale.

1-An equilateral triangle with base length equal to the width of the base and height less than the height of the pyramid.

2-

An isosceles triangle with base length equal to the width of the base and height less than the height of the pyramid.

3-

An isosceles triangle with base length equal to the width of the base and height equal to the height of the pyramid.

4-

A rectangle with length and width equal to the length and width of the base of the pyramid.