Which of the following represents naturalistic observation?

a. Researchers watch and record how elementary school children interact on the playground.

b. Researchers bring participants into a laboratory to see how they respond to a puzzle with no solution.

c. A principal looks at the relationship between the number of student absences and their grades.

d. A social worker visits a family home and gives feedback on family interactions.

e. Two grandparents sit in the front row to watch their grandson’s first piano recital.