Respuesta :
In the case when the experiment should be repeated so it should be like the smiling group.
Repetition of the experiment:
In the case when the experiment should be repeated so here the smiling group should have more positive mood since the research should be depend upon the mood and the expression that should be a scientific experiment based on the smiling and the changing in the mood.
Also at the same time, we analyze the neutral mood just like the control group. Also, the smiling group should be more positive.
hence, the option d is correct.
learn more about experiment here: https://brainly.com/question/13501071