All of the following statements are true about the price-to-sales ratio EXCEPT:（）

A. users of the ratio believe that sales information is subject to less manipulation than any other data item.

B. price-to-sales ratio is fairly constant by industry.

C. advocates of the ratio believe that p sales growth is a requirement for a growth company.

男，60岁。右上腹疼痛伴黄疸3月余。B超检查肝脏多发性散在性占位病变，lAFP（-）。临床拟诊为继发性肝癌，其诊断的关键（）

A.肝穿刺

B.找出原发灶和解除胆道梗阻

C.CT

D.MRI

E.肝血管造影