Define R as the region bounded by the graphs of f(x) = 3x – x^2 and the x-axis. Which of the following represents the volume of the solid of revolution formed by rotating R about the y-axis? ∫0 3 π(3x^3 – x^4 )dx ∫0 3 2π(3x – x^2 )dx ∫0 3 2πxdx ∫0 3 2π(3x^2 – x^3 )dx ∫3 0 2π(3x^2 – x^3 )dx