In "a model of christian charity," john winthrop likens the persecution suffered by the puritans and their opportunity to prove themselves to be god's chosen people to the story of the

That would be the story of the ancient Israelites.
The Puritans like Wintrop were not able to express their faith openly and keep their normal lives at those times so he had to emigrate. This he compared to the ancient Israeli people and their struggles to preserve their fate. This sermon shows his opinion how a ideal Christian community should look like. "A city on the hill" phrase is also from this sermon.

The answer should be a.