The correct answer is option 4 - Gram Sabha, Panchayat Samiti, Zilla Parishad. In the 3-tier Panchayati Raj System in India, the first level is the Gram Panchayat at the village level, which consists of the Gram Sabha (village assembly) and is responsible for decision-making at the local level. The second level is the Panchayat Samiti (also known as Block or Taluka Panchayat), which is a group of Gram Panchayats in a block or taluka and is responsible for coordination and implementation of various programs and services in the block/taluka. The third and highest level is the Zilla Parishad, which is at the district level and acts as the apex body of the Panchayati Raj System in the district. The Zilla Parishad is responsible for overall planning, development, and administration of the district.