Consider the following function: f (x)= x^2 What is the approximate area under the curve from x=0 to x=1 when Riemann sum is obtained by dividing the interval into two equal subintervals (hence, using two subrectangles) and taking the rightmost function value for each subinterval for the approximation?

A.) 5/8
B.) 1/2
C.) 3/8
D.) 3/4