I think its A. This is what I found on google.
Memos have a twofold purpose: they bring attention to problems and they solve problems. They accomplish their goals by informing the reader about new information like policy changes, price increases, or by persuading the reader to take an action, such as attend a meeting, or change a current production procedure.
or this
¨A memo’s purpose is often to inform, but it occasionally includes an element of persuasion or a call to action. All organizations have informal and formal communication networks. The unofficial, informal communication network within an organization is often called the grapevine, and it is often characterized by rumour, gossip, and innuendo. On the grapevine, one person may hear that someone else is going to be laid off and start passing the news around. Rumours change and transform as they are passed from person to person, and before you know it, the word is that they are shutting down your entire department.
One effective way to address informal, unofficial speculation is to spell out clearly for all employees what is going on with a particular issue. If budget cuts are a concern, then it may be wise to send a memo explaining the changes that are imminent. If a company wants employees to take action, they may also issue a memorandum. For example, on February 13, 2009, upper management at the Panasonic Corporation issued a declaration that all employees should buy at least $1,600 worth of Panasonic products. The company president noted that if everyone supported the company with purchases, it would benefit all¨
- Memos: Purpose and Format from lumen technical writing