21. What is the area of the region enclosed by the graph of the equation $x^2+y^2=|x|+|y|$? $\textbf{(A)}\ \pi+\sqrt{2}$ $\textbf{(B)}\ \pi+2$ $\textbf{(C)}\ \pi+2\sqrt{2}$ $\textbf{(D)}\ 2\pi+\sqrt{2}$ $\textbf{(E)}\ 2\pi+2\sqrt{2}$