C. Increased crash energy
Answer:
i believe it would be urbanisation as the defination for urbanisation is Urbanization refers to the population shift from rural areas to urban areas, the gradual increase in the proportion of people living in urban areas, and the ways in which each society adapts to this change.
It was the CSS Virginia that was the Confederacy's first ironclad vessel, built on the hull of the Union ship, USS Merrimack, although it turned out to not be terribly useful in wartime.