Answer:
D. Expansion of labor unions
Step-by-step explanation:
The result that completes this diagram is "the expansion of labor unions".
During the rise of the factory system, factories were unsafe places to work in, workers work for long hours and are poorly paid. Also, factories were poorly lit and cluttered. It was killing and polluting people and at the same time putting workers under much stress and pressure. It was at this time, during the second half of the 19th century, the trade/labor union movement started. Workers began to organize themselves in order to improve their lot through collective action. The formation of the labor unions started the reformation which eventually helped those that were unfairly treated.