Overcrowding and slums developed a. as a result of failed agriculture. b. as people move to cities to look for work. c. as people move to cities to sell their agricultural products. d. all of the above.

The correct answer is B.

Before the industrialization process, most job positions were in the countryside, where people worked in agriculture and farming activities. In fact, these sectors were very unproductive because there was an excess of workers in the sector and, hence, everybody earned very low wages.

When factories and mass production appeared, many people moved from the countryside to the cities seeking for better job positions in the factories, where they could earn a higher salary than in agriculture or farming. This massive arrival of people to cities triggered the development of slums and other overcrowding problems.

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