A Psychologist Reports a Single Case of a Disorder, Detailing

A psychologist reports a single case of a disorder, detailing the person's feelings and responses. This research strategy is

A) weak because it rarely provides information we can generalize to others with the disorder.
B) weak because it confuses correlational data with experimental data.
C) very strong and widely used in abnormal psychology.
D) rarely used in abnormal psychology because few people are willing to examine their own lives closely.