Answer :
Merrimack beasts name given to the Union's first ironclad vessel that revolutionized naval warfare.
The correct option is B
USS Merrimack was a steam frigate, which the Confederation reconditioned in 1862 by covering it with metal armor to confront the ships of the North in the American Civil War. Merrimack was the first of the six screw frigates that began operating in 1854, it was named after the river of the same name.
