Answer :
Answer: Option 'D' is correct.
Step-by-step explanation:
Since we have given that
Cross section taken perpendicular to the base of a cone.
A cone has one circular base with two slant heights and a vertex connected by its curved side.
Cone is 3-D shape formed by triangle by rotating along the height of the triangle.
When a plane cuts the cone and be perpendicular to the base of the cone.
Then the shape of cross section will be triangle in 2D structure.
And base of triangle becomes the diameter of cross section.
Hence, Option 'D' is correct.