Answer: their
Explanation: The sentence is addressing car buyers having something, in this instance a choice. When the subject is possessive, you use their. Such as, the car buyers ate <em>their</em> lunch.
Contract negotiation is the process of give and take the parties go through to reach an agreement. Or, as they often say in business, "you don't get what you deserve; you get what you negotiate." ... For practical tips on tactics at the negotiating table, check out Nolo's article Contract Negotiation: 11 Strategies.
B is the correct answer. Hope this helps!
