Context please so we can understand what you mean
Answer: Basic Research
Explanation: Basic research is done specifically to add to our general understanding of psychology, like distinguishing the components of extraversion or predicting the time it takes a person to determine whether an object is a face or another object.
3 its number 3 because half of our life time we still are looking for that answer but i still not sure it hope it helps
D, I'm pretty sure it's D