A direct marketing channel

Please indicate which of the following is an example of a direct marketing channel?
Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer.
a
Producer – Wholesaler – Retailer – Consumer.
b
Customer – Retailer – Consumer.
c
Producer – Consumer.
d
Customers – Resellers – Company – Suppliers.
e
Every answer except “Producer – Consumer” is correct.