Really, really basic Towing Question

[TM42]

I'd be really embarassed to ask this, if I hadn't read enough of this forum to know that you all are super nice people. We are going to pick up our new TM 2720Sl next weekend, and I forgot to ask the dealer how long the trailer wire connector needed to be. They're closed now, and I need to get this ordered ASAP to get it in time. I'm thinking 6' should do it, but I'd hate to come up short. I've looked and looked and can't find a referance to the length anywhere. If someone would be so kind as to respond.... Thank you!
Michelle