A sequence is defined by xn+1=1−2xnxn3,0<xn<(12)2/3.x_{n+1}=\frac{1-2x_n\sqrt{x_n}}3,\qquad0<x_n<\left(\frac12\right)^{2/3}.xn+1=31−2xnxn,0<xn<(21)2/3. If xn→ax_n\to axn→a, find aaa. A13\frac1331B25\frac2552C67\frac6776D12\frac1221E14\frac1441