Ring formation problem

Apr 2014
3
0
http://imgur.com/D49GHpq
I'm fairly confused as to how C makes D, I'm guessing it's the major product as it has something to do with carbocation stability? I've drawn out a mechanism for forming B by protonating the ring and then that being attacked by the double bond but I can't see how it would be the other way round. Many thanks if you can help!