A tour group is going to travel to Tibet in late July. The leaflet of the travel agency suggests: ① It will be cold in the morning and evening, so prepare coats and cotton-padded clothes; ② Prepare a

A tour group is going to travel to Tibet in late July. The leaflet of the travel agency suggests: ① It will be cold in the morning and evening, so prepare coats and cotton-padded clothes; ② Prepare a parasol. The Qinghai-Tibet Plateau is the highest plateau in the world, with an average elevation of over 4,000 meters. It is called "the roof of the world". The mountains are covered with snow all year round, and glaciers crisscross. Cold, lack of oxygen, thin air and little precipitation are the main natural environmental characteristics of the Qinghai-Tibet Plateau. So the temperature changes greatly from day to day-① coat cotton-padded clothes in the morning and evening; The air is thin and the light is strong-② prepare umbrellas and sunglasses; High altitude and low pressure can easily cause altitude sickness-③ People with heart, brain and blood diseases should not travel to Tibet; There is little precipitation in most parts of Qinghai-Tibet, and southern Tibet is in the monsoon region. July and August are rainy seasons, and there is more rain-④ Take a raincoat.

So choose: a.