Explanation: A GaAsFET (Gallium Arsenide Field-Effect Transistor) preamplifier offers a significant advantage in modern VHF radio receivers due to its ability to provide **high gain and a low noise floor**. GaAsFETs excel at higher frequencies (VHF, UHF, and microwave) because their material properties allow electrons to move faster than in silicon, resulting in less inherent noise generation. When placed as the first amplification stage in a receiver, a GaAsFET preamplifier boosts weak incoming signals significantly (high gain) while adding very little additional noise of its own (low noise floor). This dramatically improves the receiver's overall sensitivity, allowing it to detect much weaker signals that would otherwise be lost in the receiver's internal noise. Option A is incorrect because selectivity is primarily determined by filters, not preamplifiers. Option B is incorrect as preamplifiers are designed for high gain, not low gain. Option D is incorrect because a high noise floor would counteract the benefit of high gain, making it harder to hear weak signals.