Answer:
In many cases, slaves were promised freedom in exchange for service.
The correct answer is nº4.
A thesis statement is used to summarize in 2-3 lines the main argument that will be developed along a much longer piece of text that usually comes right after. In this case, in nº 4 describes very broadly the most important characteristics of the Industrial Revolution (IR) period, including both some causes and consequences of this process. The new technologies that were implemented to enhance the productivity of the manufacturing activities led to new production systems, that required different type of employees and a big number of them. Industrial workers lived in cities so there was an important shift of population from rural to urban areas, that could offer more job positions than the agricultural industry in the countryside. All this meant a great change in society and in the way of life of the majority of the population in industrialized regions.
The other sentences in this introduction paragraph only mention specific aspects of the IR process. In turn, number 4 provides a relation of the main aspects that have to be commented for sure if speaking about industrialization.
After the death of Timur in 1405, power began to shift from migrating peoples to sedentary populations living in large centralized empires. After about 1683, when the last Ottoman campaign against Vienna failed, the great empires for which this period is so famous began to shrink and weaken
