To deliver the fastest possible time to first render, you should minimize the number of:

To deliver the fastest possible time to first render, you should minimize the number of:

• The number of CSS classes
• The number of critical JavaScript functions
• The number of critical resources
• The number of critical HTML classes

Correct answer is:

• The number of critical resources

Explanation:  To deliver the fastest possible time to first render, we need to minimize three variables:

• The number of critical resources.
• The critical path length.
• The number of critical bytes.

A critical resource is a resource that could block initial rendering of the page. The fewer of these resources, the less work for the browser, the CPU, and other resources.
Read more here: https://support.google.com/partners/answer/7336426