Which of the following is never reported as a ceiling?

The correct answer pertains to the definition of ceilings in aviation weather reporting, specifically regarding how they are determined based on cloud layers and visibility conditions.

A ceiling is defined as the height above the ground of the lowest layer of clouds or obscuring phenomena that is reported as being broken (more than 5/8 of the sky covered) or overcast (more than 7/8 of the sky covered). In this question, the scenario presented in the choice describes a layer of fog that is hiding 7/8 of the sky. While this condition obscures visibility, fog itself does not qualify as a cloud layer in terms of ceiling reporting. The presence of fog does not create a ceiling because ceilings are defined with respect to clouds, and fog lacks the defined structure associated with cloud layers.

In contrast, a broken layer of clouds or a layer over fog that obscures a significant portion of the sky are both directly related to cloud cover and can be reported as ceilings. Moreover, vertical visibility into precipitation that hides the entire sky is also reported as a ceiling because it indicates the extent of the visibility above the ground.

Thus, the choice indicating a layer of fog hiding 7/8 of the sky does not constitute a ceiling under FAA regulations.