Explanation:

- In acephalous tribal political systems, there is no central leader or chieftain. Social order is maintained by kinship, lineage heads, or councils. No individual holds overriding power.

- In cephalous tribal political systems, a single leader or chieftain plays an important role in governing and maintaining social order. The chieftain's decisions are respected and authority is centralized.

- Bureaucratic systems are typical of more complex, larger societies, not tribal ones, involving many officials and structured hierarchies.

- Oligarchy refers to rule by a few powerful individuals or families, not by a single chieftain or leader.

Correct answer: Option: 2 - Cephalous