You are on a geography field trip and have been given the task of finding out how much time individuals have spent in a shopping mall. Which of the following data collection techniques do you feel would be most appropriate to find out this information?
a. Conducting surveys with shoppers in the mall to directly ask them how long they have been there
b. Using wifi or Bluetooth technology to track the amount of time individual devices have been in the mall
c. Observing and recording the entry and exit times of individuals in the mall
d. Asking the mall management for aggregate data on average length of time spent by shoppers
