单选题
71. An experienced climber could scale to the mountain summit and back in 11 hours.
The mountain is a famous tourist destination. It is popular for climbers to scale to the summit. From the base, it typically takes 7-9 hours to climb to the top, and 4-5 hours to descend. While it is possible to climb the mountain in a single day, it is not recommended. 'Bullet Climbers', as they are called, can easily succumb to altitude sickness – the only remedy is to come down the mountain immediately. One does not need to be an experienced climber to attempt the mountain challenge, but a reasonable level of fitness is required to avoid undesirable problems.