How does a narrow-band roofing filter affect receiver performance?
It improves sensitivity by reducing front-end noise
It improves intelligibility by using low Q circuitry to reduce ringing
It improves blocking dynamic range by attenuating strong signals near the receive frequency✓الإجابة الصحيحة
All these choices are correct
الشرح
A roofing filter sits in the first IF, ahead of the later amplifier and AGC stages, so strong signals a short distance from the receive frequency are attenuated before they can compress those stages. That raises blocking dynamic range; it does not improve sensitivity, and narrow filters tend to add ringing rather than reduce it.