Answer:C)Triangulation
Explanation:
Triangulation is a technique in which data is collected from diffrent sources and using that data as a verification of what is being researched. It can also refer to using different research methods to solve one issue or study one phenomenon.As we can see in our case above a criminologist uses police records and observation to study marijuana use among college students, so he is using different sources or different research methods.
It can be useful if one wants to reduce bias in their study, because gathering information from diffrent sources is better than relying on one source because it can provide a broader view of the topic.
