Which of the following is a sign that an email could be a phishing attempt?

The presence of an overly urgent subject line is indeed a common indicator of a phishing attempt. Phishing emails often employ urgency to create a sense of panic or haste, prompting the recipient to act quickly without taking the time to assess the email's legitimacy. Scammers utilize this tactic to lower the recipient's guard and elicit immediate responses, such as clicking on malicious links or providing personal information.

In evaluating the other options, while being addressed by name, a matching display name, and having proper spelling and grammar might typically indicate a legitimate email, they are not definitive signs of security. Phishers can easily personalize emails and create convincing identities to appear credible. Therefore, the combination of urgency in the subject line serves as a critical red flag, alerting recipients to approach the email with skepticism.