How did civilians on the East Coast work to protect US ships?

Explanation:

Though coastal defense was generally within the purview of the Army, the Navy became more involved in the late 19th century with coastal defense ships, generally called monitors. These monitors were turreted ironclad warships inspired by USS Monitor; as well as coastal ships which closely followed her design, the term "monitor" also encompassed more flexible breastwork monitors which had a modest armored superstructure and were thus more seaworthy. These also featured modern rifled breech-loading guns.

Monitor-style ships were used extensively in offensive roles during the Civil War, but were impractical for ocean service and offensive action abroad. They were, however, ideally suited for harbor defense with their shallow draft and large guns. Postwar, Civil War-era monitors were dispersed to important harbors, including San Francisco on the west coast. From the 1870s to the 1890s, larger and more powerful breastwork monitors were produced, such as the Amphitrite class, while the ocean-going navy was slow to make the transition to steel hulls and armor plating. An improvement on the monitor concept was the coastal battleship, such as the Indiana class of the 1890s.

As a result of the Spanish–American War and the acquisition of Hawaii and the Philippines, by 1900 the Navy was committed to ocean-going battleships, and ceased building monitors; however, some of the vessels remained in service up to World War I in combat-prepared roles, and as training or auxiliary vessels thereafter.

the answer is c     : )

explanation:

i don't have an explanation because i don't know, but i think the answer is c because i googled it and google is right : ) just kidding google isn't allways right but the answer is still c. i hope this !

it is a because im a fod nigba