Let f(x)=ax2+bx+cf(x) = ax^2 + bx + cf(x)=ax2+bx+c. If f(f(x))=xf(f(x)) = xf(f(x))=x for all xxx, which condition must be true?
a=0,b=1,c=0a=0, b=1, c=0a=0,b=1,c=0
a=0,b=−1,c=anythinga=0, b=-1, c=anythinga=0,b=−1,c=anything
a=1,b=0,c=0a=1, b=0, c=0a=1,b=0,c=0
a=1,b=1,c=1a=1, b=1, c=1a=1,b=1,c=1