Which of the Following Is a Drawback to the Observational

Multiple Choice

Which of the following is a drawback to the observational method?

A) People's behaviours inevitably change when they are being observed.
B) Certain behaviours only take place rarely or in private.
C) No interesting or important questions can be answered using this method.
D) The observational method is statistically unreliable.
E) The observational method cannot impact a well-accepted theory.