TOEFL Listening: TPO-TOEFL阅读TPO - 72891WAH4NXVS0K8N$

Why does the author include the following information: "At first, paper was made in relatively small sheets that were pasted together, but by the beginning of the fourteenth century, very large sheets – as much as a meter across – were available."? A. To provide evidence that the development of papermaking techniques was very slow B. To explain why paper was never as cheap as it has become today C. To make the point that paper allowed artists to develop paintings that were more expressive and complex D. To prove that paper was more popular with artists who used large sheets, than it was with book printers, who used smaller sheets