AMC 12 2025a Problem 9

Let $w$ be the complex number $2+i$, where $i=\sqrt{-1}$. What real number $r$ has the property that $r$, $w$, and $w^2$ are three collinear points in the complex plane?

\textbf{(A)}\frac34 \textbf{(B)}1 \textbf{(C)}\frac75 \textbf{(D)}\frac32 \textbf{(E)}~\frac53