"People of the Same Trade Seldom Meet Together,even for Merriment

Multiple Choice

"People of the same trade seldom meet together,even for merriment and diversion,but their conversation often ends in a conspiracy against the public." This quote from Adam Smith is referring to which of the following business relationship terms? 

A)  Combination 
B)  Cooperation 
C)  Collusion 
D)  Collaboration