A person can be more effective in negotiations if he/she does all of the following,EXCEPT:

A) demonstrating his/her attention through communication and listening skills.
B) agreeing on issues that are unsolvable at that moment.
C) walking away or taking a break if necessary.
D) using agendas,questioning,and summarizing techniques.

Agreeing on issues that are unsolvable at that moment would not make the person more effective in negotiations. In fact, it could potentially harm their position in the negotiation. The other options - demonstrating attention, taking breaks if needed, and using effective communication techniques - are all strategies that can increase effectiveness in negotiations.