Cadillac CTS-V ipod connector cord?

So my mom got this new cadilliac and it's supposed to be able to connect to an ipod but when we tried using the usb cord that comes with the ipod it doesn't work. After searching online I came to this page: http://www.gm.com/vehicles/parts/ipod/
and I don't know which one of the 2 options to get. I don't really understand the difference either. It's a Cadillac CTS-V. My mom doesn't know what she's doing when it comes to cars so I thought I'd ask lol. Someone please help I am sooooo confused!!!!
 
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