Since the average of the numbers is 150, they could all be 150, or they could be dispersed around 150. The iron law is that the differences between each of the numbers and 150 must all cancel out. On to the statements, separately first.
In Statement (1), if none of the numbers is less than 150, the only way their differences from 150 could net to zero is if all of the numbers were 150. Therefore all of the numbers are 150, we can answer definitively, and Statement (1) is sufficient.
Statement (2) is sufficient on the same grounds as Statement (1).
The correct answer is (D).