In relation to a WordPress theme, which of the following statements is correct about the index.php file?

In relation to a WordPress theme, which of the following statements is correct about the index.php file?

• It is a fall-back file that is used to serve all the content to the browsers for rendering.
• It is used to provide the meta-data for communication to WordPress about a theme.
• It can be used to style the HTML that exists on the other required file.