Find the x and y coordinates of all inflection points.f(x)=x +21xWhat is/are the inflection point(s)? Select the correct choice below and, if necessary, fill in

Find the x and y coordinates of all inflection points.f(x)=x³ +21x²What is/are the inflection point(s)? Select the correct choice below and, if necessary, fill in the answer box to complete your choice.A. The inflection point(s) is/are(Type an ordered pair. Use a comma to separate answers as needed.)B. There are no inflection points.