In Farewell Address, which of the following sentences from the excerpt best supports Washington's belief that national unity is of the highest importance?
a) "But as it is easy to foresee that, from different causes and from different quarters, much pains will be taken, many artifices employed to weaken in your minds the conviction of this truth;"
b) "Citizens, by birth or choice, of a common country, that country has a right to concentrate your affections."