In a Research Study,two Conditions Were Arranged

Multiple Choice

In a research study,two conditions were arranged.Participants in Group X were subjected to a strong smell,and participants in Group Y were not subjected to any smell.Participants in both groups were then tested on an eye-hand coordination task.What is wrong with this study?

A) Participants were not randomly assigned to the two groups.
B) Participants in Group Y should also have been exposed to a "placebo" smell.
C) There is evidence of experimenter bias.
D) Nothing is wrong;the experiment is fine as it is.