Today, some states have right-to-work laws, which
question 7 options:
prohibit closed shops and union shops.
ban unions.
establish a minimum wage.
prohibit discrimination against minorities in hiring practices.

Reading this may help you to answer, although I do find the information a little unclear myself. The question states "some states" which suggests in my opinion the answer is the closure of union shops?

the values of the selma marchers was to bring   their ability to vote into law. mlk was not hat march, which was protesting toward lbj