The most accurate statement for law enforcement from the options provided is:
C) Law enforcement officers are required to uphold the law.
This statement reflects the primary duty of law enforcement officers, which is to enforce laws and maintain public order.
The other options contain inaccuracies: A) Law enforcement agencies operate independently and are not employed by the court system. B) The recruitment and training of police officers are typically handled by individual police agencies or commissions, not the Department of Homeland Security. D) Ordinary police officers are indeed required to understand how to gather evidence as part of their investigative responsibilities.