Step 1: Understanding the Concept:
A three-tier structure refers to a system organized at three distinct hierarchical levels. The question asks to identify which of the given systems follow this model in India.
Step 2: Detailed Explanation:
\[\begin{array}{rl} \bullet & \text{Co-operative credit society: The rural co-operative credit system in India has a three-tier structure: Primary Agricultural Credit Societies (village level), Central Cooperative Banks (district level), and State Cooperative Banks (state level).} \\ \bullet & \text{Consumer Protection Act: It establishes a three-tier quasi-judicial machinery for consumer grievance redressal: District Commissions, State Commissions, and the National Commission.} \\ \bullet & \text{Panchayati Raj: The 73rd Constitutional Amendment Act provides for a three-tier system of local self-government in every state: Gram Panchayat at the village level, Panchayat Samiti at the block level, and Zila Parishad at the district level.} \\ \end{array}\]
Since all three systems have a three-tier structure, the correct answer is "All of these".
Step 3: Final Answer:
Co-operative credit society, the Consumer Protection Act machinery, and Panchayati Raj all have a three-tier structure.