A mass $M$ is suspended from a spring of negligible mass. The spring is pulled a little and then released so that the mass executes SHM of time period $T$. If the mass is increased by $m$, the time period becomes $\frac{5 T}{3}$. Then the radio of $\frac{m}{M}$ is [2003]
(A) $\frac{3}{5}$
(B) $\frac{25}{9}$
(C) $\frac{16}{9}$
(D) $\frac{5}{3}$