Explanation: Maximizing a SART's (Search and Rescue Transponder) detection and effective range relies on fundamental radio propagation principles. SARTs transmit at 9 GHz, which is an X-band radar frequency primarily limited by line-of-sight. 1. **Height:** Mounting or holding the SART as high as possible extends its radio horizon, allowing its signal to reach more distant searching radars on ships or aircraft. This is crucial for all line-of-sight communications. 2. **Vertical Position:** Search radars typically transmit and receive with vertical polarization. Placing the SART in a vertical position ensures its antenna polarization matches that of the searching radar, maximizing the received signal strength and thus detection effectiveness through optimal signal transfer. Option B is incorrect because placing it in water would minimize its height, severely limiting range. Option C is incorrect as SARTs typically have fixed power outputs and no user-selectable "high" power position. Option D is incorrect because mounting it horizontally would cause significant signal loss due to cross-polarization with the vertically polarized search radar signals, dramatically decreasing detection range.