设平面均匀薄片所占的闭区域D由曲线-|||-=(x)^2, x+y=2 围成,则此薄片的质心坐标为-|||-()-|||-A (-dfrac (1)(2),dfrac (8)(5))-|||-B (dfrac (1)(2),dfrac (8)(5))-|||-C (-dfrac (1)(2),dfrac (4)(5))-|||-D (-dfrac (3)(2),dfrac (8)(5))