Explanation: A vertical loop antenna typically exhibits a bi-directional radiation pattern. This means it has two primary directions of maximum radiation (or reception) 180 degrees apart. For a vertical loop, these maximums occur in the directions that lie within the plane of the loop itself. Conversely, the antenna has minimum radiation or reception (often called nulls) in the directions broadside, or perpendicular, to the plane of the loop. This directivity makes it useful for nulling out interference or focusing power in specific directions. Option A is incorrect because "omni-directional" implies equal radiation in all horizontal directions, which a loop does not have. Option B is also incorrect for the same reason, as "non-directional" is synonymous with omni-directional. Option C describes the pattern of a horizontal dipole antenna, where the nulls are off the ends, not a loop.