A.
You are just like a toad having the delusion of eating the meat of a swan! Ridiculous! We can never agree to you. We need not to continue our negotiation.
B.
Sorry! Absolutely impossible! We can never agree with you on your current terms. I suggest we take a break so that you can adjust your terms.
C.
How dare you attach these unreasonable terms! We can never agree to you. We need not to continue our negotiation.