When line forms when a plane and a cylinder intersect ?

If the plane and the cylinder intersect perpendicular to each other, then the resulting line will form a circle. It the cylinder and the plane intersect horizontally to each other, the resulting line will form a rectangular prism.
Hope that helped =)

B. 2 1/2 feet. multiply 2.5 inches by 12 to get thirty inches then divide by 12 to get 2.5 feet