Final answer:
The best study design for the Quixlet research study would be Prospective experimental randomized control (c) because it allows researchers to control variables and randomly assign participants to different groups.
Step-by-step explanation:
The best study design for the Quixlet research study to determine the validity of a new test to diagnose COVID-19 in asymptomatic college students would be Prospective experimental randomized control design (c) because it allows researchers to control variables and randomly assign participants to different groups.
By using this design, researchers can compare the effectiveness of the new test in detecting COVID-19 among asymptomatic college students.
Using a control group will help establish a baseline for comparison, and randomization helps minimize bias and increase the validity of the study results.