As IT manager of Some Corporation, you are frequently asked to recommend what medium of ...

As IT manager of Some Corporation, you are frequently asked to recommend what medium of communication would be appropriate for a given purpose. In which of the following situations would you recommend the use of IM?
A.    The line manager needs to send a message to the HR manager detailing how an employee flouted company rules and needs to be disciplined.
B.    The sales manager needs to send to the COO confidential information relating to a tender that the company is submitting.
C.    The marketing manager needs to present next year’s marketing budget and plan to the Board of Directors.
D.    The operations manager needs to direct the work of the support staff working on repairing a key piece of machinery and get real-time updates from them.