What warning might a browser display if a certificate is invalid?

A browser typically issues a warning message indicating that a certificate is invalid to alert users of potential security risks. This warning often includes changing the appearance of the address bar, such as altering its color to a noticeable hue like maroon. This visual cue serves to emphasize the security concern and prompts users to exercise caution before proceeding.

In this context, the correct response highlights the browser’s proactive role in safeguarding users against sites that may not properly encrypt data or may be impersonating legitimate sites. The other options do not accurately describe standard browser behavior concerning invalid certificates. For instance, a secure symbol indicates a valid certificate, while refreshing the page or changing the URL to a different domain are not typical actions taken by browsers when encountering certificate issues. Such actions may mislead users rather than inform them about the security status of a website.