i hope you meant plats, i couldn't find information on "plots".
although the funding of seattle is dated in 1851, when a group of inmigrants from illinois led by arthur deny arrived to alki piont, the correct answer is may 1853. on this date arthur denny, carson boren and dr. david s. maynard laid out the first plats for the town of seattle. the process was filled with setbacks, as they discussed the orientation of the streets. should they follow the cardinal points of the compass or parallel the shore of elliot bay.
in the end both ideas were used forming yesler way, were roads mismatch.
these plats established the present day street grid.
i think that the best answer to this question is b)
to be completely honest none of these answers are correct, but b seems to be the most likely. the real reason france and more specifically napoleon sold the louisiana territory was because he needed money for the war against britain.