Two blocks of masses 3 kg and 5 kg are connected by a metal wire going over a smooth pulley. The breaking stress of the metal is $\frac{24}{\pi} \times 10^2\text{ N m}^{-2}$. What is the minimum radius of the wire? (take $g = 10\text{ m s}^{-2}$)
(1) 1250 cm
(2) 1.25 cm
(3) 125 cm
(4) 12.5 cm