Answer:
C, they analyze police reports about crimes reported by victims
Explanation:
Option A is wrong because is disregard hard crimes that conducted by blue-collar people (such as theft, store robbery, or even gang attacks).
Option B and D are wrong because 'Potential' victims do not always translate to actual victims, This will make the data that collected by the firm become misleading. They wouldn't find out the type of crimes that often happen in real life and wouldn't be able to design a proper solution for them.
Option C is the best choice from the available options. Even though it's not perfect. There are a lot of crimes that often goes unreported by the victims (such as domestic abuse)