Initially the force of the spring on the lower block must be upward where is the mass of the identical blocks. So, initially, the force of the spring on the upper block must also be , but now the force points downward. Therefore, when the string breaks, the upper block will feel a force of downward, one due to the spring and one due to gravity. Therefore, the acceleration of the upper block will be downward. Therefore, answer (E) is correct.
