If f(x)=x2+bx+cf(x) = x^2 + bx + cf(x)=x2+bx+c and f(f(0))=f(c)f(f(0)) = f(c)f(f(0))=f(c), which of the following must be true?
c2+bc=0c^2 + bc = 0c2+bc=0
b+c=0b + c = 0b+c=0
b=cb = cb=c
c=1c = 1c=1