Two blocks \(A\) and \(B\) of masses \(3m\) and \(m\) respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in the figure. The magnitudes of acceleration of \(A\) and \(B\) immediately after the string is cut, are respectively:

1. \(\dfrac{g}{3},g\)
2. \(g,g\)
3. \(\dfrac{g}{3},\dfrac{g}{3}\)
4. \(g,\dfrac{g}{3}\)
| 1. | \(1~\text{cm}\) | 2. | \(2~\text{cm}\) |
| 3. | \(0.5~\text{cm}\) | 4. | \(\sqrt2~\text{cm}\) |