Consider the solid that lies above the rectangle (in the xy-plane) $R = [-2, 2] \times [0, 2]$,
and below the surface $z = x^2 - 2 y + 4$.

(A) Estimate the volume by dividing R into 4 rectangles of equal size, each twice as wide as high, and choosing the sample points to result in the largest possible Riemann sum.
Riemann sum =

(B) Estimate the volume by dividing R into 4 rectangles of equal size, each twice as wide as high, and choosing the sample points to result in the smallest possible Riemann sum.
Riemann sum =

(C) Using iterated integrals, compute the exact value of the volume.
Volume =