Answer: d)The cross sections of the slices are disks.
Explanation:The slicing method deals with the elimination of the horizontal layer of the solid body .It is considered that disk method is the special case of the slicing method.
Disk method consist of the slices that are used for the estimated volume of the solid body of revolution that are known as disk.The solid body revolving around a line and its volume is estimated.Thus, the correct option is option (d).