Choice "C" is correct. The auditor's communication with those charged with governance should be two-way: those charged with governance should also communicate relevant matters to the auditor.
Choice "b" is incorrect. The auditor may discuss matters with management prior to communicating those matters to those charged with governance.
Choice "a" is incorrect. The auditor may discuss the planned scope and timing of the audit with those charged with governance, but should be careful not to compromise the effectiveness of audit procedures by making them too predictable.
Choice "d" is incorrect. Written communications to those charged with governance should include a limitation on the use of the communication, indicating for whom it is intended and warning that it should not be used by others.