How would you react to an E2 who "smart mouths" you in formation?

Here's the background. You're a senior E5. Your troops are in formation and you're handing out work for the day. You hand out an assignment to a fresh E2 with less than a year in and only a few months at your command. They blatantly complain and tell you to choose someone else. You calmly tell them they will do this task and they tell you to shove it and give it to someone else. How do you react?