Answer:
C. Use data published in business journals.
Explanation:
Here, using data that has already been published by business journals is said to be the vest because they have already done all surveys, interviews and questionnaires involved in its research.
Example is the Savvy study revealed that around a fifth of UK customers had used click and collect services to buy food during the past year. However, some of the most recent innovations in online retailing have been in the area of click and collect, such as Sainsbury's Chop Chop which allows shoppers to order up to 25 items using the app.