The auditor must gather sufficient and appropriate evidence during the course of the audit. Sufficient evidence must: （ ）审计师必须在审计过程中收集充分和适当的证据。充分证据必须：（ ）
选项：

A:be well documented and cross-referenced in the audit documents. .在审计文档中做好记录并相互参照。;
B: be based on sources that are external to company. 基于公司外部的来源。;
C:provide evidence that prove or disprove an audit objective/assertion.提供证明或反驳审计目标/认定的证据。;
D: be persuasive enough to enable the auditor to issue an audit report. 具有足够的说服力，使审计师能够出具审计报告。