"The management team at Mercury, a department store, has received feedback from the customer service department that the store's exchange policy creates a lot of stress for customers. The customers need to visit several counters before their product is finally exchanged with another. All attempts to interact with customers to study the problem have failed because consumers chose to become hostile, rather than giving any constructive feedback. The team is now planning to conduct market research by monitoring people s behavior as they wait in line for products to be exchanged. What type of research is the store conducting?