Find the odd socio-cultural category (tribes vs religion): Select the option that is not an Indian tribal/ethnic group but a major organized religion/community.

Introduction / Context:
Odd-one-out tasks in general knowledge frequently rely on a single, stable attribute that partitions items into incompatible categories. Here, three entries are well-known indigenous tribal communities of India, usually grouped under the umbrella of Scheduled Tribes or recognized ethnic groups. One entry, however, denotes a large, organized religion/community with its own doctrine, clergy, places of worship, and pan-regional membership. This categorical mismatch cleanly identifies the outlier.

Given Data / Assumptions:

• Bhils: a major tribal community primarily in western/central India (e.g., Rajasthan, Gujarat, Madhya Pradesh).
• Todas: a pastoral tribal community of the Nilgiri Hills in Tamil Nadu.
• Nagas: a collective term for several tribal groups in Northeast India (notably Nagaland and adjoining regions).
• Sikhs: adherents of Sikhism, a monotheistic religion founded in the Punjab region, with global presence and formal religious institutions.

Concept / Approach:
Classify each option by socio-cultural type. Tribal groups are indigenous, endogamous communities with distinctive languages, customary law, and localized territories. A religion/community like Sikhism transcends tribe/ethnicity, has scripture (Guru Granth Sahib), codified practices, and institutional structures (gurdwaras) spanning regions and nations. The presence of a religion among tribal identifiers yields a 3-vs-1 split.

Step-by-Step Solution:

Verification / Alternative check:
Cross-check institutional markers: tribes are classified under ethnographic and constitutional categories; Sikhism is cataloged under religions, with doctrines, rites, and clergy. The domains do not overlap.

Why Other Options Are Wrong:
Bhils, Todas, and Nagas all denote indigenous tribal identities, aligning with each other and not with an organized religion label.

Common Pitfalls:
Do not conflate “community” with “tribe.” Many communities exist, but the criterion here is tribal identity vs religion.

Final Answer:
Sikhs