Answer:
Group Boycotting.
Step-by-step explanation:
In this scenario, Mark, a real estate broker, teamed up with Chris, another real estate broker, in an effort to not do business with a cross-town broker. Hence, Mark and Chris be accused of Group Boycotting.
Group Boycotting can be defined as the process of having two or more parties (competitors) come together and reach an agreement not to do business with their close rivals in the same industry. A group boycott is a violation of antitrust law because the conspiring parties refuse to do business with another for their selfish interests or ulterior motives.