In a study of community policing neighborhood meetings, I randomly select ten meetings across the city of Toronto over one year to use as my sample. I assign two research assistants to attend each meeting to collect data. They are instructed to only record the topics discussed about the sex, race, and age of teh attendees. This is an example of:

a. Survey research

b. participant-as-observer field research

c. interrupted time series

d. double blind field research.