Respuesta :
Answer
D.Experimental bias
Explanations
Experimental bias occurs when a scientist performing a research influence the results in order to portray a certain outcome.In this case,Ron unintentionally smiled when then subject was showing to act as expected.In doing so,"smiling" the subject was able to identify the correct answer.
It’s D experimental bias because experimental bias is also called experimenter bias which means process where scientists preform real research influence the results in order to portray a cartoon out come