How can you tell that his statement from “The Eternal Frontier” is an opinion?

In 1900 there were 144 miles of surfaced road in the United States.

A. It contains a statistic.
B. It can be proved true.
C. It cannot be proved true.
D. It comes from a reference book.

Explain the effect of the juxtaposition of the following lines that serve as a beginniing to the new section that begins on page nine: anguish. german soldiers-with their steel helmets and their deaths-head emblem. still, our first impressions of the germans were rather reassuring.