Yes, the option is available under Contests -> Edit or create a contest -> Contest Automation -> "Winner Selection" but:
The concept around WP Contest Creator is to make your participants help you promote your contest by telling others. This encourages them to engage the social networks and such to spread the word. We have been asked the same question before about picking the winner randomly, but if this was the case then people would just join themselves and "hope" they win.
By "hoping" they could win in a random selection has opposite effect of sharing, since people wouldn't want other people to join because the odds of winning at a random pick is greater the less people join a contest. So for example if 10 people join, and you are 1 of the 10 people your odds of winning are 1 in 10. On the other hand if 100 people join your odds of winning are dramatically reduced to 1 in 100. This is why contests based on random selection are not good to help you on a viral contest campaign.