The correct answer is option 4, Kaziranga National Park. Kaziranga National Park is a UNESCO-approved World Heritage Site located in Assam, India. It is renowned for its significant conservation efforts for the Indian one-horned rhinoceros and is home to a diverse range of flora and fauna. The park is known for its vast grasslands, wetlands, and dense forests, providing a unique ecosystem for various species.
Option 1, Meenakshi Temple in Madurai, is a popular Hindu temple but is not a UNESCO World Heritage Site.
Option 2, Writers` Building in Calcutta, is a historic colonial building but is not a UNESCO World Heritage Site.
Option 3, Purana Qila in Delhi, is an ancient fort but is not a UNESCO World Heritage Site.
Therefore, the correct UNESCO-approved World Heritage Site from the given options is option 4, Kaziranga National Park.