According to MLA guidelines, which of these is the best paraphrase of the following sentence from the passage?

These rural farmers were entirely dependent on potatoes and entirely unprepared when, in 1845, a new form of plant disease spread across Ireland, destroying their beloved crop.
A.
Irish peasants relied solely on potatoes; they were not ready when a new potato blight appeared in 1845. The disease ruined potatoes all over Ireland (Murray 4).
B.
These rural farmers were completely dependent on potatoes and entirely unprepared when, in 1845, a new form of plant disease spread across Ireland, destroying their beloved crop (Murray 4).
C.
There were other farmers who grew corn and barley. However, they exported most of these goods to Britain so that they could make more money (Murray 4).
D.
Entirely dependent on potatoes, these farmers were not prepared when, in 1845, a new form of plant disease spread across Ireland, destroying their beloved crop (Murray 4).