AG Mechanics CDE Practice Exam 2026 - Free AG Mechanics Practice Questions and Study Guide

The footing should be placed above the frost line because a frost line is the maximum depth at which the ground freezes in winter. Placing the footing above the frost line helps prevent the ground from freezing and heaving under the footing, which could potentially cause structural damage to the building or structure. Keeping the footing above the frost line ensures stability and longevity of the structure.

Options B, C, and D are incorrect because placing the footing at ground level, below the frost line, or below water level can lead to various issues such as frost heave, foundation instability, and water damage.