Without additional context, it is difficult to provide a specific answer. However, if this question is referring to the history of child labor laws in the United States, then the correct answer would be:
B. They would soon be required to learn a trade.
Starting in the late 19th and early 20th centuries, child labor laws were enacted in the United States to protect children from exploitation in the workplace. These laws established minimum age requirements for working, limited the number of hours that children could work, and required that children attend school. Additionally, some laws required that children under a certain age learn a trade, which was seen as a way to prepare them for future employment while also ensuring that they were not being exploited by employers. However, it should be noted that child labor laws varied by state and were not fully standardized until the passage of federal laws in the mid-20th century.