Step 1: Identifying Coaliferous Units.
The Barakar Formation is recognized for its coal-rich strata, making it the most coaliferous unit within the Gondwana Supergroup. Other formations, such as the Talchir and Karharbari, also contain coal, but the Barakar Formation stands out in terms of coal content.
Step 2: Conclusion.
Therefore, the correct answer is the Barakar Formation.
Final Answer: \boxed{(B)}
| Group-I | Group-II | ||
| P | Ramgundam | 1 | Chhattisgarh |
| Q | Raipur Formation | 2 | Kaladgi |
| R | Bagalkot Group | 3 | Marwar |
| S | Sonia Sandstone | 4 | Godavari |
Match the following basins in Group I with their corresponding formations in Group II. \[ \begin{array}{|c|c|} \textbf{Group I} & \textbf{Group II} \\ P. Cauvery & 1. Lohardih \\ Q. Damodar & 2. Tiratgarh \\ R. Chhattisgarh & 3. Raniganj \\ S. Indravati & 4. Kallamedu \\ \end{array} \]