As the Number of Goods and Services Increases, How Is

As the number of goods and services increases, how is barter affected?  

A)  Barter becomes easier because the chance of there being a double coincidence of wants increases. 
B)  Barter becomes harder because the chance of there being a double coincidence of wants increases. 
C)  Barter becomes easier because the chance of there being a double coincidence of wants decreases. 
D)  Barter becomes harder because the chance of there being a double coincidence of wants decreases.