Choice "A" is correct. In a typical comfort letter, the accountants express an opinion (i.e., positive assurance) concerning the financial statements' compliance (as to form) with the pertinent accounting requirements of the SEC.
Choice "c" is incorrect. No assurance is generally provided in a comfort letter regarding the operation of an entity's internal control.
Choice "d" is incorrect. A typical comfort letter is addressed to the underwriters of the securities. Government Auditing Standards and the Single Audit Act are not applicable to a comfort letter related to the issuance of securities.
Choice "b" is incorrect. Negative assurance (not positive) is typically provided regarding unaudited condensed financial information.