Critical Reasoning (CR) | Re: Scientists often study modern-day primates in an attempt to better

Scientists often study modern-day primates in an attempt to better understand the behavior and lifestyle of their now-extinct primate ancestors. This is a questionable technique, however, as primate groups have not always been exposed to the same types of external stimuli. Most primates now being observed have been seriously impacted by the loss of their former habitat due to deforestation.

Which of the following, if true, most seriously undermines the argument above?

(A) By studying the response