Which of the following is an example of a grave liner?

A grave liner is a protective container that is placed in the ground to hold the casket and provide some degree of protection against the ground and elements. It serves the primary purpose of preventing the surrounding soil from collapsing into the grave and can help maintain the integrity of the burial site.

The choice "Sectional" refers to a type of grave liner that is constructed in sections, enabling it to be assembled in the grave. This type of liner not only provides a protective barrier but is also designed to facilitate easier installation. The sectional design allows for flexibility and can be particularly beneficial in certain burial conditions.

In contrast, the other options represent different types of burial containers or vaults used in mortuary practices but do not fall under the specific category of grave liners. A combination case is typically a type of casket that can double as a shipping container, while top seal and air seal vaults offer a higher level of protection and sealing for caskets but are not necessarily classified as grave liners. These vaults are used primarily to protect against water infiltration and environmental factors, rather than solely serving the function of supporting the ground above the grave.