Answer:
4. the South
Step-by-step explanation:
There states with "right to work" laws in all regions of the country, except for the Northeast, but only in the South are all states so called "right to work states", meaning that all of the Southern states have enacted these types of laws.
According to the right to work laws, workers should not be obliged to pay union fees or to belong to an union. Advocates of these laws defend them on the basis of personal freedom, while opponents argue that these laws weaken unionization, and that promote the use of many union services by workers who do not pay fees (a phenomenon known as freeriding) since the government demand laws to represent all workers, regardless of whether they have paid a fee or not.