What are the standard dimensions of a leader board ad?

The selected answer option, 728x90, is correct because the standard dimensions for a leaderboard ad are 728 pixels by 90 pixels. The leaderboard ad is a popular display ad format that typically appears at the top of a webpage, providing significant visibility for advertisers. This size is widely used across many websites and ad networks due to its ability to effectively capture user attention while maintaining a clean and non-intrusive design. It is commonly displayed as a horizontal banner and is optimized for desktop viewing, although it can also be adapted for mobile-friendly layouts in some cases. The other dimensions listed, such as 300x250 and 250x300, are for different ad formats, not the standard leaderboard.