Harriet Beecher Stowe wrote Uncle Tom's Cabin in response to the passage of the second Fugitive Slave Act, which required which of these?

A) All freed slaves were to travel freely to any state they chose.
B) All captured escaped slaves were to be returned to their masters.
C) Slaves were to choose any trade of interest when they were freed.
D) Escaped slaves were to remain free as long as they were in a northern state.