Explanation: Polarization is a fundamental characteristic of an electromagnetic wave, including satellite signals, describing the orientation of its electric field component. If the electric field oscillates in a single plane, it's linearly polarized (e.g., vertical or horizontal). If the electric field rotates as the wave propagates, it's circularly or elliptically polarized. Option A correctly identifies this definition. The electric field is the component that interacts most directly with antennas, inducing a voltage across them. Option D is incorrect because, by convention in radio theory, polarization is defined by the electric field, even though the magnetic field component is always present and oriented perpendicular to the electric field. Options B and C are incorrect because polarization is an intrinsic property of the *signal itself*, not its orientation relative to any specific type of antenna. While antennas must be designed or oriented to *match* the incoming signal's polarization for efficient transfer, the antenna does not define the signal's polarization.