Which of the Following Options Is the Best Description of Concealment

Which of the following options is the best description of concealment?

A) It involves hiding the presence of the observer and any recording equipment to prevent individuals from changing their natural behavior.
B) It involves hiding the presence of recording equipment but not the presence of a human observer to prevent individuals changing their natural behavior.
C) It involves hiding the purpose of the study from individuals who are being observed to prevent them from changing their natural behavior.
D) It involves hiding the researcher's records of observed behavior from individuals who are being observed to prevent them from changing their natural behavior.