Which of the following best describes 'spam' in the context of email?

The term 'spam' in the context of email refers specifically to unwanted electronic junk mail. This includes unsolicited messages that are typically sent in bulk, often for the purpose of advertising. Spam is characterized by its lack of relevance to the recipient, often containing promotions or offers that the recipient did not request.

While promotional emails can sometimes be legitimate and welcomed (such as those from companies that a user has opted to engage with), spam is generally considered intrusive and can clutter a user's inbox, making it difficult to find important messages. Unwanted electronic junk mail encompasses a broader range of unsolicited content, which is why the definition aligns perfectly with option C.

In contrast, important notifications and system updates are usually essential communications that users expect to receive, making those options unsuitable for defining spam.