Osha has authority over the employers of
a. state government workers.
b. local government workers.
c. coal miners.
d. maintenance electricians.

It would be that the OSHA has authority over the employers of "A. state government workers," although it should be noted that the OSHA also has a wide authority over many other types of employers. 

Primary sources are usually  more accurate and are written by someone who experienced it or witnessed it. secondary sources are those who heard of it after the fact that can lose details and or twist the event in a light that benefits them.