Cone is a three-dimensional figure that has one circular base and one vertex.
Right Cone: A right cone is a cone in which the vertex is aligned directly above the center of the base. The base need not be a circle here.
Right Circular Cone: When the base of a right cone is a circle, it is called a right circular cone. In a right circular cone, each point on the circle is equidistant from the vertex of the cone.
Oblique Cone: When the vertex of a cone is not aligned directly above the center of its base, it is called an oblique cone.
Correct Answer: D
Step 1: The base radius is 2 units.
Step 2: So, the area of the base is π × 2 × 2 = 12.57 sq units.