Which footing type supports more than one column?

The option related to combined footing is the correct answer because this type of footing is specifically designed to support more than one column, especially when those columns are spaced closely together or when the load from the columns results in excessive soil bearing pressure if separate spread footings were used.

Combined footings help distribute the load from multiple columns across a larger area of soil, which reduces the pressure on the ground and enhances stability. They can also assist in maintaining alignment between columns that may be positioned near property lines or when dealing with variations in soil conditions.

In contrast, while spread footings can support individual columns or walls, they do not provide support for multiple columns simultaneously. Cantilever footings are typically used in situations where one side of the footing extends beyond the load it supports, primarily used for walls or overhanging conditions. Continuous footings support walls rather than multiple columns, spanning the length of the wall instead of individual point loads. Thus, combined footings uniquely provide the necessary support for more than one column.