Explanation:

To activate JavaScript, the button attribute is used. Let's delve into the details below to understand why this is the correct option.

HTML Attributes:
HTML attributes are used to provide additional information about an HTML element. They are placed within the start tag of an element and are made up of a name-value pair. These attributes help in modifying the behavior and appearance of an element.

JavaScript:
JavaScript is a programming language that adds interactivity to websites. It is used to create dynamic and interactive web pages. JavaScript can be added to an HTML document in two ways:

1. Inline JavaScript: JavaScript code can be directly added to the HTML document using the script tag. For example:
```html

```

2. External JavaScript: JavaScript code can also be placed in an external file with a .js extension and included in the HTML document using the script tag. For example:
```html

```

Button Attribute:
The button attribute is an HTML element used to create a clickable button on a webpage. It can be used to trigger an action or perform a specific task when clicked by the user. This can include running JavaScript code, submitting forms, or navigating to another page.

Activating JavaScript with a Button:
To activate JavaScript using a button, we can attach an event listener to the button element. This event listener listens for a specific event, such as a click event, and executes the associated JavaScript code when the event occurs. Here is an example:

```html
Click Me


```

In the above example, the JavaScript code inside the event listener function will be executed when the button with the id "myButton" is clicked. This allows us to perform any desired action or manipulation using JavaScript.

Conclusion:
In conclusion, the button attribute is used to activate JavaScript by attaching an event listener to the button element. This allows us to execute JavaScript code when the button is clicked, providing interactivity and dynamic functionality to web pages.