The Sangam Age is a significant period in the history of Tamil Nadu, making option 3 - Tamilnadu the correct answer. During this period, which is estimated to have lasted from 300 BCE to 300 CE, the famous literary works known as the Sangam literature were produced. These texts provide valuable insights into the culture, society, and political climate of ancient Tamil Nadu. The term "Sangam" refers to assemblies or gatherings of Tamil scholars, poets, and artists, where the literature was composed and discussed. The Sangam Age is considered a golden period of Tamil literature and is highly respected by scholars and enthusiasts of Tamil history and culture. It is important to note that the Sangam Age is not associated with Benaras, Allahabad, or Khajuraho, making options 1, 2, and 4 incorrect.