What Is One of the Advantages Associated with Naturalistic Observation

What is one of the advantages associated with naturalistic observation?

A) Some behaviours occur infrequently and, therefore, are unlikely to be observed.
B) People may behave differently when they know they are being observed.
C) Naturalistic observation does not require verbal instructions and, therefore, can be used to study the behaviour of infants and toddlers.
D) Some socially undesirable behaviours are unlikely to be witnessed by an unknown observer in natural settings.