An HR manager is explaining the importance of objectivity to performance appraisers. Which can prevent legal challenges?

a$.$ The performance appraisal relates directly to the responsibilities of the job.

b$.$ The results of the appraisal are subject to internal arbitration at the employee's request.

c$.$ The appraisal system is not evaluated or changed for at least a $5-$year period.

d$.$ Negative documentation is not included in the personnel file.