Answer:
The Sampling Bias
Step-by-step explanation:
Here in this question, the owner is only getting information about the customers which are coming to the mall on weekdays only while neglecting the response which could have been received on weekends.
Therefore this can be termed as a Sampling Bias. The perfect way to go after this question is to ask the customers which are coming to the mall on weekends as well as weekdays, throughout the day.
Hope this helps. Good luck.