The render tree contains:

The render tree contains:

• visible content
• content of the page
• the DOM
• the styles of the page

Correct answer is:

• visible content

Explanation: The CSSOM and DOM trees are combined into a render tree, which is then used to compute the layout of each visible element and serves as an input to the paint process that renders the pixels to screen.

Read more here: https://support.google.com/partners/answer/7336524