The correct answer is (b) Chamoli.
The Valley of Flowers is a high-altitude meadow located in the Garhwal Himalayas in the Indian state of Uttarakhand. It is a UNESCO World Heritage Site and is known for its alpine flowers, including more than 300 species of orchids. The valley is located in the Chamoli district of Uttarakhand, about 200 kilometers from the state capital of Dehradun. The best time to visit the Valley of Flowers is from July to September, when the flowers are in bloom.
The other options are incorrect. Uttarkashi is a district in the Garhwal Himalayas in the Indian state of Uttarakhand. Pauri Garhwal is a district in the Garhwal Himalayas in the Indian state of Uttarakhand. Rudraprayag is a district in the Garhwal Himalayas in the Indian state of Uttarakhand.