Which statement is TRUE according to police’s practice in Chinese mainland?

A、If a person is missing, you wait and contact the police the next day.;

B、If a person is missing, you will have to wait 24 hours to contact the police.;

C、If a person is missing, you contact the police immediately, and the police will look into the case as soon as possible.;

D、If a person is missing, you contact the police immediately, but the police will take action 24 hours later.