Answer:
c. machines watching people
Explanation:
Machines watching people refers to a phenomena whereby via employment of specialized machinery, an organization is successfully able to observe the activities of it's customers and at the same time also track data relating to their identity and other credentials.
In the given case, the sophisticated system entails deciphering the customer shopping pattern and the merchandise sold during a period whereas the payment mechanism of cards also helps in tracing down the identity to ensure no unscrupulous person can go unnoticed.
Thus, it's a case of machines keeping a watch or surveillance on the customers and their identity.