In a circle of diameter 40cm,the length of a chord is 20cm.Find the length of the minor arc of the chord

Question

$\begin{array}{1 1}(A)\;\large\frac{10\pi}{3}\normalsize cm&(B)\;\large\frac{20}{33}\normalsize cm\\(C)\;\large\frac{20\pi}{3}\normalsize cm&(D)\;\large\frac{12\pi}{5}\normalsize cm\end{array}$