Question: Pippalada was an ancient Indian Vedic sage who was known to have written which ancient Sanskrit text, embedded inside Atharva Veda?
Sentence (from "Prashna Upanishad"): It is a Mukhya (primary) Upanishad, and is listed as number 4 in the Muktika canon of 108 Upanishads of Hinduism.
Relevant evidence: No