When you set up an A/B test in an Email Batch Program (EBP), you have the option of manually sending the winner, or having the Marketo system send the winner Automatically. If you have forgotten, or cannot tell when looking at a past Approved EBP, there is a trick you can use.
When looking at the Control Panel in the Email Program, there is an option to "View A/B Test" in the square panel for selecting the Email Assets. When you click on this "View Test," at the bottom there will be something that says either "Send Report" or "Send Notification". "Send Report" is for a Manual A/B test, and "Send Notification" is for an Automatic A/B test.