Which of the following roof types contains a center elevation along a ridge line?

Pitched roofs are designed with a slope that allows for effective water drainage and snow load management. A key characteristic of pitched roofs is the presence of a central ridge line that serves as the highest point, where two sloping planes meet. This elevation enables the roof to shed precipitation and prevents water accumulation, which could lead to structural issues.

In contrast, flat roofs do not have a noticeable elevation or slope along a ridge line, making them less effective at managing water runoff. Green roofs typically incorporate vegetation and may have some slope for drainage, but they don't feature a pronounced central ridge line. Butterfly roofs have two sloping sections that meet in the middle, creating a valley rather than a distinct ridge, which is not the same as the elevated ridge characteristic of pitched roofs. Hence, the distinctive center elevation along a ridge line clearly identifies pitched roofs as the correct answer.