Psychologists Generally Assert That About 50% of All People Will

Psychologists generally assert that about 50% of all people will eventually experience at least one psychological disorder. A major problem with that assertion, or with any other percentage, is that

A) psychologists in different parts of the U.S. have different rules for diagnosing psychological disorders.
B) results of random-sampling studies have been vastly different from those of representative-sampling studies.
C) classification of marginal cases depends upon the strictness of the criteria.
D) certain disorders such as bipolar disorder are very serious, even though they are not common.