Tibetans live on the Qinghai-Tibet Plateau with high altitude and large temperature difference between day and night. Even in a day, there are often changes in wind, rain and snow. Tibetans often describe climate change as "four seasons in one mountain, but different days in ten miles". Tibetan robe is made of good material and has strong cold-proof effect. When the temperature rises, you can easily take off a sleeve to adjust the temperature, which is also beneficial to life and travel. Tibetan robe has a big waist. In addition, it is beneficial to labor production. When Tibetans are grazing, working and farming, and the weather is changeable, they just need to take off their sleeves to adjust the temperature. It is also convenient to take off their sleeves and tie them around their waist and bend over to work. As a result, they gradually formed a habit that Tibetans usually wear only one sleeve when the temperature is normal. Tibetan robe is a common dress of Tibetan people, and it is also the most remarkable feature that distinguishes it from other ethnic groups.

So choose: C.