下列分解因式正确的是（  ）

A：$x^2-y^2={\left(x+y\right)}^2$

B：$m^2+2mn+n^2={\left(m-n\right)}^2$

C：$a{b}^{2}x-aby=ab\left(x-y\right)$

D：$4x^2-8xy+4y^2=4{\left(x-y\right)}^2$