General exam question G9B05

WhyA horizontal dipole HF antenna less than 1/2 wavelength high has an azimuthal radiation pattern that is almost omnidirectional at elevation angles higher than about 45 degrees. A horizontal dipole mounted less than about half a wavelength above ground loses much of the sharp broadside/end-null shape it would have in free space at high elevation angles, and its azimuthal pattern at those high angles becomes nearly omnidirectional, answer C. Going higher doesn't make the pattern "unpredictable," antenna height clearly does affect the pattern (so it isn't simply irrelevant), and a low dipole doesn't eliminate off-the-end radiation, if anything the pattern becomes rounder rather than more directional, so A, B, and D are wrong.