Which of these accurately describes Google’s experimentation tool?

It’s a powerful testing tool that helps boost campaign performance for a small additional cost. 

It’s a powerful testing tool that uses a simulated ad environment to determine which creative or audiences will perform best.

It’s a powerful testing tool that shows all users two versions of an ad so you know which people prefer. 

It’s a powerful testing tool that lets you assess the effectiveness of creatives, audiences, or other variables.