This class represents a question on the Alcohol Use Disorders Identification Test (AUDIT) Assessment Instrument. This abstract class exists primarily to re-define the generic AssessmentInstrument.item.question property to the AuditAssessment.item.question. In other words, of all the possible questions on all the possible assessment instruments, we are explicitly identifying the ten Audit questions. Note that because this class is abstract, implementers would likely not instantiate this class, but rather the six concrete sub classes.