A manager wanted to learn how customers would react to some new product displays. To collect this information, she posted employees near the display and had them record how long customers looked at it$,$ whether they picked up the item, and if they took the item with them. In this case, she is using$\_\_\_\_\_\_\_\_$ for her market research.

Question $1$ options:

A$)$

situation analysis

B$)$

secondary data

C$)$

in$-$depth interviews

D$)$

observational data

E$)$

focus groups