Which of the Following Statements Is Generally Correct About the Appropriateness

Which of the following statements is generally correct about the appropriateness of audit evidence?

A) Auditors' direct personal knowledge, obtained through observation and inspection, is of higher quality than information obtained indirectly from independent outside sources.
B) To be reliable, audit evidence must be either valid or relevant, but need not be both.
C) Client accounting data alone may be considered sufficient appropriate audit evidence to issue an unmodified opinion on client financial statements.
D) Appropriateness of audit evidence refers to the amount of corroborative evidence to be obtained.