Final answer:
To avoid comb filtering, the microphone should be parallel to the table top.
Step-by-step explanation:
To avoid comb filtering when a microphone is positioned near a table top, it should be parallel to the table top. Comb filtering occurs when sound waves from multiple sources interfere with each other. When the microphone is parallel to the table top, it captures the sound waves directly, reducing the interference caused by reflections off the table surface.