What is 'mixed content' in a secure web page and how does active vs passive mixed content differ in risk?

• A.Active mixed content (scripts, stylesheets, iframes over HTTP on an HTTPS page) allows full MitM attacks - a network attacker can modify the HTTP resource to inject code executing in the page's origin. Modern browsers block active mixed content entirely. Passive mixed content (images, audio, video) allows content replacement but cannot execute code - browsers may show a warning but often allow it
• B.All mixed content is equally risky; there is no distinction between active and passive mixed content
• C.Mixed content is only a risk for users on public WiFi; home users are not affected
• D.Mixed content only occurs when a page has both HTTP and HTTPS links in the same file