A Researcher Theorizes That People Are Likely to Perspire More

Multiple Choice

A researcher theorizes that people are likely to perspire more when telling embarrassing stories than when telling funny stories.Volunteers are asked to record a memory of an embarrassing or a funny incident and their perspiration is measured.On some days,but not others,the lab where the recordings are done is very hot.Based on this information,what should be of most concern to the researcher?

A) placebo effects.
B) experimenter expectancy effects.
C) the presence of a confounding variable.
D) determining an operational definition of embarrassment.