ACT Problem 7

$$\begin{array}{lcl} 7.\;What\;is\;the\;radius\;of\;a\;circle\;which\;is\\ described\;by\;the\;equation\\ x^2+2x+y^2-4y=4?\\ \\ (A)\; 1\\ (B)\; 2\\ (C)\; 3\\ (D)\; 4\\ (E)\; 5\\ \end{array}$$