What would be the best way for the marketing manager of a supermarket to find out how consumers move through the

What would be the best way for the marketing manager of a supermarket to find out how consumers move through the

store?

Question 2 options:

a) 

None of these methods would be very good.

b) 

have an interviewer go through the store with each customer

c) 

give customers a questionnaire after they have finished shopping

d) 

install checkout counters at the end of each aisle

e) 

observe customers with hidden cameras