How to capture submitted variables from contact form

How do I capture a submitted variable from the Jetpack contact form to display a custom success message based on the user’s submission?

I have a dropdown in the form for identifying what the message is concerning, but can’t find a way to isolate it on the success page. I would like a different paragraph based on each of these options:

[contact-field label='What is your message concerning?' type='select' options='Appointment Request,Submit a Resume,Volunteer/Internship,Other'/]

I have already done some searching and found this on the topic, but I still need to pull the variable – Reference Topic

Thanks in advance!

http://wordpress.org/extend/plugins/jetpack/