I believe the answer is: C. Law enforcement officers are mainly required to uphold the law.
Because of this the scope of action which can and cannot be done by law enforcement is limited in a very strict regulation. If the law enforcement disobey this limitation, the suspect could even sue the law enforcement and all of the charge can be nullified.
Congress attempt to provide a legal basis for its authority
The progressives tried to help children by limitng maximum hours of labor and in establishing a minimum age for children to be allowed to work.
There were also mandatory laws in different states for children to attend school.
The Progressives believe that government should take an active participation to solve the problems in a society like poverty, education, woman and children rights, job opportunities and best conditions for living.