(A) The idea of taking over another nation and claiming it as your own is referred to as imperialism. Often countries try to take over other countries because they are more powerful than the weaker country and they are trying to control the economic and political affairs of weaker countries or regions.
(B) A heavy warship of a type built chiefly in the late 19th and early 20th centuries, with extensive armor and large-caliber guns.
(C) ** A group of ships sailing together, engaged in the same activity, or under the same ownership. An example would be the US Navy.
EXPLANATIONS BELOW
Concept note-1: -A group of ships are called flotilla or naval flotilla.
Concept note-2: -convoy, vessels sailing under the protection of an armed escort. Originally, convoys of merchant ships were formed as a protection against pirates.
Concept note-3: -ˈflēt. : a group of warships under one command. : a group of ships or vehicles that move together or are under one management.