this problem features a 'headless modifier' (i.e., a modifier that doesn't contain a subject and verb of its own), followed by a comma, before the main clause.

such modifiers must refer to the noun that begins the following clause, and which therefore appears directly after the comma.

in this case, the modifier is clearly intended to refer to the pennsylvania navy, so that is what should follow the comma. this observation narrows the choices to a and e.

choice e doesn't make much sense: not only is 'served the revolutionary way for america' nonsense from the idiomatic standpoint, but this sentence also seems to imply that the revolutionary war lasted until 1798.

therefore, choice a wins.