Eila Is Participating in a Psychological Experiment for One of the Graduate

Eila is participating in a psychological experiment for one of the graduate students at her university.She is pretty confident that she knows the true intent of the study and is trying to answer the questions accordingly.This is because the graduate student who designed the study unintentionally left hints as to what the true purpose of the experiment was,and Eila has figured out that purpose.A common pitfall in experiments,Eila has been influenced by:

A) intentionality.
B) the Rosenthal effect.
C) observer bias.
D) demand characteristics.