诊断小肠扭转的首选方法是（）

A.X线平片

B.钡剂灌肠

C.消化道造影

D.B超

E.CT

Based on the AIMR Standards of Professional Conduct, which of the following statements is least likely to be a violation of Standard Ⅲ(D) , Prohibition against Misrepresentation（）

A. An analyst tells a prospective client that investment grade bonds involve less default risk than junk bonds. 

B. A bond trader tells a client that he can assist the client in all the client’s investment needs: equity, fixed income, and derivatives. 

C. An investment manager recommends to a prospective client an investment in mortgage IO strips because they are guaranteed by an agency of the federal government.