Professor anderson studies memory in people who have had strokes. professor schmidt studies people who claim to have clear memories of events that happened over three decades ago. such research on the extremes of memory:

Helps us to know how memory works

Explanation:

Anderson studies effect of stroke on memory and he studied this by conducting a experiment on people who has strokes.

During his whole experiment he tested the memory of people who had stokes in his early life.

They claimed that they have clear memories of the events which took place decades ago, this research helps us to know how memory works in the people who has stokes a time ago.

the answer is d

hope this and you do good