Choice "B" is correct. When the auditor believes there is substantial doubt about the ability of the entity to continue as a going concern for a reasonable period of time, there is a responsibility to consider the adequacy of the client's disclosure of such circumstances.
Choice "d" is incorrect. There is no requirement to disclaim an opinion solely due to a going concern issue.
Choice "a" is incorrect. The auditor does not have a responsibility to communicate to the audit committee whether management's plans can or cannot be effectively implemented.
Choice "c" is incorrect. A qualified or adverse opinion is only required in situations where there is no adequate disclosure.