What Is the Advantage of Using Job Performance as a Job

What is the advantage of using job performance as a job analysis method?

A) This method can provide information about standard as well as nonstandard and mental work.
B) Direct exposure to jobs can provide a richer,deeper understanding of job requirements than workers' descriptions of what they do.
C) With this method there is exposure to actual job tasks as well as to the physical,environmental,and social demands of the job.
D) This method focuses directly on what people do in their jobs,and thus it provides insight into job dynamics.