Which of the Following Was Discussed as a Potential Limitation

Which of the following was discussed as a potential limitation of naturalistic observation?

A) The settings in which naturalistic observations typically occur tend to have low external validity.
B) Naturalistic observation often makes improper use of random assignment.
C) The observer's presence may disrupt or influence the behaviour of the person or animal he/she is watching.
D) Naturalistic observation relies too heavily on the use of archival data about the person or animal being observed.