Which quadratic equation is equivalent to (x+2)^2+5(x+2)-6=0?
A. (u+2)^2+5(u+2)-6=0 where u= (x-2)
B. u^2+4+5u-6=0 where u =(x-2)
C. u^2+5u-6=0 where u =(x+2)
D. u^2+u-6=0 where u=(x+2)