关于高层建筑设置转换层的目的，下列何种说法是正确的？（）

A. Because publishers wanted higher quality paper.
Because paper made from rags deteriorated too quickly.
C. Because wood pulp had become too expensive.
D. Because the supply of rags was insufficient.

A. Gathering non-relevant materials.
B. Stealing another person's ideas.
C. Sharing notes with someone else.
D. Handing m assignments late.