A massless and inextensible string connects two blocks \(\mathrm{A}\) and \(\mathrm{B}\) of masses \(3m\) and \(m,\) respectively. The whole system is suspended by a massless spring, as shown in the figure. The magnitudes of acceleration of \(\mathrm{A}\) and \(\mathrm{B}\) immediately after the string is cut, are respectively:
1. | \(\dfrac{g}{3},g\) | 2. | \(g,g\) |
3. | \(\dfrac{g}{3},\dfrac{g}{3}\) | 4. | \(g,\dfrac{g}{3}\) |