Do not use a pickle fork. It will damage the boot. Use a large ball peen hammer and give a few hard smacks at arrow C. This will momentarily elongate the hole and cause the link to come off. Problem solved.
There it is. :D
I don't like having to do that, but I will if it's all I have to work with.
One small addition would be to put the nut back on 3 or 4 threads before you smack it since you have to re use the joint as it will protect the threads when you miss arrow C.
Now here's hoping he has a ball peen hammer.