The Textbook Discussed Several Examples of Case Studies

The textbook discussed several examples of case studies. In what way was the study of H.M. most different from other case studies such as the one about Nadia?

A) H.M. was an adult, whereas Nadia was a child, and therefore the study of H.M. came with fewer ethical concerns.
B) H.M. could not consolidate new memories, and therefore might not have been vulnerable to feeling bored and fatigued from repeated sessions with an experimenter or researcher.
C) H.M. had a rare tumor, which made the findings non-generalizable to non-clinical populations.
D) The data obtained from H.M. were mostly through naturalistic observations, whereas the data generated from studying Nadia were mostly through a microgenetic approach.