Answer:
D.) to see how the problem has been approached before
Step-by-step explanation:
When researching a problem, the priority is to find a solution and is important for it to be the best possible solution to avoid issues that could arrive in the future. The researcher needs to analyze all pros, cons and the implications of each possible solution. In order to understand the implications of the problem it is really helpful to know if the issue has been tackled before, and if so, what were the implications and consequences of the methods used. So it is important to look at the past, but only as a guide, and is necessary to review past information carefully and critically, to come up with the best possible solution for the current situation.