Which of the following limits equals the definite integral ∫02(x2+4x)dx after the algebra in the summand has been fully simplified?
a) n→∞limi=1∑n(n34i2+n28i)
b) n→∞limi=1∑n(n32i2+n28i)
c) n→∞limi=1∑n(n38i2+n216i)
d) n→∞limi=1∑n(n38i2+n28i)