Which of the following would you use to define the background color of a table in a web page?
attribute
domain
extension
tag
The correct answer is: attribute.
In HTML, you would use the 'bgcolor' attribute to define the background color of a table. For example:
```html
<table bgcolor="#ff0000">
<!-- table content here -->
</table>
```
The 'bgcolor' attribute allows you to specify the background color using either a color name or a hexadecimal color code.