In the diagram below, a diameter of each of the two smaller circles is a radius of the larger circle. If the two smaller circles have a combined area of 1 square unit, then what is the area of the shaded region, in square units?[asy]
size(4cm);
filldraw(scale(2)*unitcircle,gray,black);
filldraw(shift(-1,0)*unitcircle,white,black);
filldraw(shift(1,0)*unitcircle,white,black);
[/asy]<spanclass=′latex−bold′>(A)</span>41<spanclass=′latex−bold′>(B)</span>31<spanclass=′latex−bold′>(C)</span>21<spanclass=′latex−bold′>(D)</span>1<spanclass=′latex−bold′>(E)</span>2π