Which of the following would give a measurement of area? Thank you

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)

Which function has the vertex at (2,6)

A. 2.3y +2 +3.1y = 4.3y + 1.6 + 1.1y + 0.4 b. + 25 - = c. 5/8x + 2.5 = 3/8x + 1.5 + 1/4x d. 1/3 + 1/7y = 3/7y