Look for familiar vs. unfamiliar terms: Most UPSC questions on Indian philosophy use classical Sanskrit names like Nyaya, Vaisheshika, Sankhya, Yoga, Mimamsa, Vedanta.
Names that sound unusual, foreign, or sect-like (e.g., Lokayata, Kapalika) are often not part of the classical systems.
Check the pattern:
• Three options usually contain well-known classical names in pairs → likely correct.
• The odd one out with uncommon or radical names → likely the answer.
Apply to this question: Lokayata and Kapalika → unusual sounding, “non-classical” → pick this as the one that does not form part of the six systems.
Tip: UPSC often hides the correct answer in the “unfamiliar/less common” names when the other options are well-known.