Which of the Following State Statutes Were Not Held to Be

Which of the following state statutes were not held to be unconstitutional:

A) an Oklahoma law requiring coal-burning plants to burn at least 10 percent Oklahoma coal
B) an Ohio law requiring employers to provide health insurance for employees
C) an Alabama law charging a special fee for hazardous waste imported into the state
D) an Arizona law restricting the length of trains in the state
E) all of the other choices were unconstitutional