Regarding the Sources of Information Used in a Performance Evaluation

Regarding the sources of information used in a performance evaluation:

A) Salespeople's reports are a very poor source of information about performance input (effort) factors.
B) A widely used (and good) source is to actively and regularly solicit opinions from customers regarding the sales rep's performance.
C) Sales managers should not be used as information sources.
D) The company's accounting records are probably the best source regarding performance input factors.
E) The company's records are the best source regarding performance output factors.