Which is an opinion statement in this article?
a. special monumental arches called triumphal arches were also erected in rome.
b. if you hold each end of a chain and let it droop between your hands, you have created a catenary curve.
c. an arch can carry more weight than a straight beam can across the same span, so it's a more powerful structure.
d. you're sure to find these lovely shapes in your town or city, too.