Choice "B" is correct. When an accountant issues to an underwriter a comfort letter containing comments on data that have not been audited, the underwriter most likely will receive negative assurance on capsule information.
Choice "a" is incorrect. Positive assurance cannot be given if the information was not audited.
Choices "d" and "c" are incorrect. A comfort letter generally covers the period from the date of the last auditor's report to the effective date of the registration. It does not provide any form of assurance on "pro forma" financial statements, nor would it include a disclaimer on prospective financial statements.