This is a sufficient assumption question, so we are looking for an answer choice that will make the argument valid.
The argument tells us that wages only increase if productivity increases notably- and that it is unlikely that wages will increase since businesses are not investing much in tech.
The flaw here is that we do not know the connection between investing in new tech and productivity. Does new tech raise productivity? Maybe, but we do not know this for sure. Could other things also raise productivity? Maybe, but we have no idea. To make this argument valid, we would need to know that the only thing that will increase productivity notably would be increasing investment in tech.
This is a perfect match for (D). E, however, does not fix the flaw. Just because the tech is not contributing to an uptick in productivity does not prove that nothing else will. Maybe workers become more productive because they get more education, or regulations that hinder productivity are repealed.