问题详情

Why does the author mention a steamship？
A. To illustrate that man can make use of sources of energy from the sea.
B. To show that a steamship is better than other kinds of ships.
C. To argue that man should use steamships.
D. To indicate that it is warmer in the ocean than on land.请帮忙给出正确答案和分析，谢谢！