Choice "C" is correct. Yes - No. If an auditor concludes that there is substantial doubt about an entity's ability to continue as a going concern and that the entity's disclosures are adequate, then the audit report may be either:
(Generally, an unmodified opinion is issued, but the auditor is not prohibited from choosing to issue a disclaimer.)
Choice "d" is incorrect. An "except for" qualified opinion would be appropriate if the entity's disclosures were inadequate.
Choice "b" is incorrect. While an unmodified opinion is generally issued, the auditor is not prohibited from choosing to issue a disclaimer; for example, in areas involving a high degree of uncertainty.
Choice "a" is incorrect, based on the explanation above.