Use Stokes' theorem to evaluate ∮_C F · dr, where C is oriented counterclockwise as viewed from above. F(x, y, z) = xy i + 2z j + 4y k, and C is the curve of intersection of the plane xz = 8 and the cylinder x²y² = 9. What is the result?
a) 16π
b) 18π
c) 20π
d) 24π