Respuesta :
Answer:
D. It took 5 years to do the study
Explanation:
I would say it is D because it makes the most sense. Researching and studying this for 5 years would mean that the person studying cannot be biased, spending their time putting thought and time into it.
Answer:
D. It took 5 years to do the study
Explanation:
Can assure this is correct!!
Have a good day~~