Read the passage and answer the question.
Just as some men like to play football or cricket, so some men like to climb mountains. This is often very difficult to do, for mountains are not just big hills. Paths are usually very steep. Some mountainsides are straight up and down, so that it may take many hours to climb as little as one hundred feet. There is always the danger that you may fall off and be killed or injured. Men talk about conquering a mountain. It is a wonderful feeling to reach the top of a mountain after climbing for hours and may be even for days. You look down and see the whole country below you. You feel God-like. Two Italian prisoners of war escaped from a prison camp in Kenya during the war. They did not try to get back to their own country, for they knew that was impossible. Instead they climbed to the top of Mount Kenya, and then they came down again and gave themselves up. They had wanted to get that feeling of freedom that one has, after climbing a difficult mountain.
To climb a mountain is often difficult because

Options

A. mountains are big hills.
B. it consumes more time.
C. prisoners often escape from camps and settle there.
D. paths are steep and uneven.