We choose $I = [-1,1]$ and write $C_{n,m}$ instead of $C_{n,m}^I$. Briefly explain why there exists a polynomial $R_4$ such that the pair $(Q_4, R_4)$ forms a very good extremal pair, i.e., a good extremal pair in which all complex roots of $Q_4$ and $R_4$ are contained in $I$.