Question

which line will change the font family to serif

Answer 1

To change the font family to serif in CSS, you would typically use the following line of code:

```css
font-family: serif;
```

You can apply this style to an HTML element like this:

```html
<p style="font-family: serif;">This text will be displayed in a serif font.</p>
```

Alternatively, if you're using a CSS stylesheet, you could define it like this:

```css
p {
font-family: serif;
}
```

This will change the font family of all paragraph (`<p>`) elements to a serif font.