How does the Constitution divide power between the three branches?

a. Power is not completely separated, allowing each branch to limit the other branches’ exercise of power.
b. Power is completely separated so each branch can act independently without interference from the other two branches.
c. Power is not clearly separated, so it is difficult to say where the power of one branch ends and that of another branch begins.
d. Power is separated, but in such a way that two branches can easily work together to thwart the efforts of the third branch to exercise its powers.

I believe the answer might be (b), but I am not sure.

Thanks to all that help!

B