题目下列整式变形正确的是（ ）A.a−(b+2c)=a−b+2ca-\left(b+2c\right)=a-b+2ca−(b+2c)=a−b+2cB.a+2(b−c)=a+2b+2ca+2\left(b-c\right)=a+2b+2ca+2(b−c)=a+2b+2cC.a−2(b−2c)=a−2b+2ca-2\left(b-2c\right)=a-2b+2ca−2(b−2c)=a−2b+2cD.a−(4b−c)=a−4b+ca-\left(4b-c\right)=a-4b+ca−(4b−c)=a−4b+c知识点：绝对值（二）、三角形的三边关系章节：第1章 有理数 / 1.2 有理数 / 1.2.4 绝对值
