Yumthang Valley is known as the ‘Valley of Flowers’ and is famous for:

The correct answer is: a) Rhododendrons.

Yumthang Valley is a high-altitude valley in the Indian state of Sikkim. It is located in the Himalayas, at an altitude of about 3,450 meters (11,300 feet). The valley is known for its beautiful scenery, including snow-capped mountains, glaciers, and rhododendron forests. The rhododendrons bloom in the spring, and the valley is then a riot of color. Yumthang Valley is also a popular tourist destination, and there are several hotels and lodges in the area.

The other options are incorrect because:

• Waterfalls are not a particularly notable feature of Yumthang Valley.
• Yak herds are common in the Himalayas, but they are not particularly associated with Yumthang Valley.
• Snow leopards are endangered animals that live in the Himalayas, but they are not commonly seen in Yumthang Valley.