The factory act of 1833
a. made it illegal for children to work in factories.
c. limited the hours a child could work.
b. made it illegal for women to work underground in the mines.
d. contained the "ten hours act."

It made it illegal for children under the age of 9 to work in factories, and limited the working day of children under 18. So depending on your definition of children, it did both a. made it illegal for children to work in factories. and c. limited the hours a child could work. 

a. and c. (technically) I think it is asking for c.
c. (I think)