What method involves in-depth study of biographies obtained through interviews, questionnaires, and psychological tests?

I believe the answer is: case-study

Case study is a form of study that being done to know the development that experienced by a certain individual or a group over a period of time, Things such as interviews, questionnaires, and psychological tests would be as a data that included as the factors to count the rate of development.

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.

well considering i can't see the graph, it's probably prices