The correct answer is: Only I and II are implicit.
The statement says that the company has announced a series of incentives to the employees who are punctual and sincere. This means that the company wants to encourage its employees to be punctual and sincere. The first assumption, “Those who are not punctual at present may get motivated by the announcement,” is consistent with this goal. If employees know that they will be rewarded for being punctual, they may be more likely to be punctual in the future. The second assumption, “The productivity of the company may increase,” is also consistent with the company’s goal. If employees are punctual and sincere, they are more likely to be productive. However, the third assumption, “The profit earned by the company may be more than the amount to be spent for the incentive programmes,” is not necessarily consistent with the company’s goal. The company may spend more money on incentives than it gains in productivity. Therefore, only the first two assumptions are implicit in the statement.