Researchers Who Operationally Define the Severity of Substance Abuse as a Total

Multiple Choice

Researchers who operationally define the severity of substance abuse as a total score on a scale with multiple questions asking research participants to indicate how often they use various types of substances are using what source of data for their operational definition?​

A) ​Direct observation.
B) ​Self-report.
C) ​Available records.
D) ​Direct observables.