Explanation: Strong broadcast signals, typically operating from 530 kHz and higher, can easily interfere with reception on an adjacent frequency like 500 kHz due to their high power and proximity. **Option B is correct** because a wavetrap (also known as a notch filter or band-stop filter) is specifically designed to attenuate or reject signals at a particular frequency or band of frequencies. By resonating a wavetrap to the interfering broadcast frequencies (e.g., around 530 kHz and up) and placing it before the receiver, the strong undesired signals are significantly reduced *before* they can overload the receiver's front end, allowing clearer reception of the desired 500 kHz signal. **Option A is incorrect**. While regenerative receivers offer good sensitivity and selectivity, "without RF amplifier stages" implies a simpler front end that might still be susceptible to overload from very strong adjacent broadcast signals before the regenerative action can provide effective rejection. A wavetrap provides targeted rejection *pre-receiver*. **Option C is incorrect**. A crystal detector receiver is a very simple, passive design with inherently poor selectivity. It would be highly susceptible to strong broadcast interference and would not effectively separate the desired 500 kHz signal from adjacent, powerful stations.