单选题 Which of the following actions is a required, rather than recommended, action under the Standard regarding diligence and a reasonable basis for a firm's research recommendation?

A. Have a policy requiring that research reports and recommendations have a basis that can be substantiated as a reasonable and adequate.
B. Compensate analysts based on measurable criteria to assess the quality of their research.
C. Review the assumptions used and evaluate the objectivity of externally generated research reports.

【正确答案】 C

【答案解析】[解析] 本题主要涉及执业操守标准Ⅴ(A)(尽职、合理的基本要求)的相关规定。根据执业操守标准Ⅴ(A)的规定，会员必须对第三方研究成果(third-party research)的独立性和客观性进行审查，并对其投资建议进行审核。因此，本题的正确选项为C。A、B选项的内容为据执业操守标准Ⅴ(A)建议遵守的内容。