题目下列各式中属于最简二次根式的是（ ）A.x2+1\sqrt{x^2+1}x2+1B.x2+x2y\sqrt{x^2+x^2y}x2+x2yC.12\sqrt{12}12D.0.5\sqrt{0.5}0.5知识点：最简二次根式章节：未标注
