Explanation: A loop antenna's directional pattern depends significantly on its orientation relative to the incoming radio wave's polarization. 1. **Vertical Loop Antenna (Option A):** When a loop is oriented vertically, it exhibits a bidirectional, figure-8 reception pattern. It is most sensitive to signals arriving *in the plane of the loop*, where the magnetic field lines optimally cut through the loop, inducing maximum current. Conversely, it has deep nulls (minimum reception) for signals arriving *broadside* to the loop, as the magnetic field lines are parallel to the loop, causing little to no net induced current. Thus, A is correct. 2. **Horizontal Loop Antenna (Option B):** A small horizontal loop antenna, when receiving vertically polarized signals, is generally *nondirectional* (omnidirectional) in the horizontal plane. Its most pronounced directional characteristic is its deep nulls for signals arriving from directly *above or below* (vertically). In this orientation, the magnetic field lines from a vertical direction are parallel to the loop's plane, preventing significant current induction. Therefore, B is also correct. Since both statements A and B accurately describe the reception patterns of loop antennas based on their orientation, option D, which combines A and B, is the correct answer. Option C is incorrect as a small horizontal loop is generally nondirectional in its plane for certain polarizations, not directional.