In one study, students took a cognitive performance test with their subject number written in ink on the first page. The experiment randomly varied the color of the ink. This subtle difference produced surprising results: Those who saw ink performed worse on the test than those who saw ink.

red; green or black                                                                                                                      

Explanation:

Cognitive performance test: the term "cognitive performance test" is also denoted as CPT, and is defined as one of the "standardized occupational therapy assessments" that scrutinizes different cognitive integration related to some functioning in various "instrumental activities" of the day-to-day context of life. It generally provides the "diagnostic utility" yet doesn't encounter the fully-functional implications.

b because thats the naswer i got

where is the passage