What is the correct definition of an ironclad?

1) a new type of iron weapon used by soldiers

2) a new type of iron armor worn by soldiers

3) a new type of warship with sides covered into iron

4) a new type of fort defense using iron

3) a new type of warship with sides covered into iron.

Explanation:

Ironclads were a crucial innovation in the history of naval warfare. The term was known for  iron-armored wooden hulls. Warships used by the The Confederacy since the year of 1861 were to combat the numerically superior Union navy. Union ironclads were also associated with North Carolina. The USS Monitor sank off Cape Hatteras on 31 Dec. 1862.

the answer would be a i think?

presidency should be the title