Question

the first -arch bridge was designed by the american engineer james buchanan eads and was opened in 1874. a steel b suspension c tweed d iron

Explanation:

The first steel - arch bridge was designed by James Buchanan Eads and opened in 1874. Steel is a common material for modern bridges due to its strength and durability. Suspension is a type of bridge structure, not a material. Tweed is a fabric and has nothing to do with bridge construction. Iron is a different metal from steel and not the correct answer here.

Answer:

A. steel