Which of the following situations below makes use of the observation method?

A. Inside the laboratory, a certain group of students found out that XYZ bacteria doubles itself every minute.
B. The manager of a certain restaurant distributes questionnaires to their customers for management survey purposes.
C. Leila is calling her friend to ask about the ingredients needed for Leche flan.
D. Jose, who is a primary witness to a crime, describes the criminal as a girl who is dark-skinned, tall, and has long hair.