Which of the Following Is an Example of the Observation

Which of the following is an example of the observation method of collecting primary data?

A) Administering a questionnaire to shoppers in a supermarket.
B) Recording the amount of time a shopper stops in front of a point-of-purchase display.
C) Asking shoppers which brand they noticed first in a shelf display.
D) Conducting a telephone survey to determine which brands of detergent are purchased by mothers with young children.
E) Using a tape recorder to gather shopper impressions of a new store layout design.