Choice "A" is correct. The auditor should discuss with those charged with governance any significant disagreements with management, whether or not satisfactorily resolved, about matters that are significant to the financial statements or to the auditor's report.
Choices "d" and "c" are incorrect. There is no requirement that the auditor's communication with those charged with governance include a justification for any of the judgments made in conducting the audit.
Choice "b" is incorrect. An auditor is required to discuss his or her judgment about the quantitative aspects of the entity's accounting principles and estimates, not the quality of the entity's earnings. Note too that that no comparison to prior year is required.