Concept:Direct selling by manufacturers removes all intermediaries who stand between the producer and the final consumer.Explanation:Middlemen include wholesalers, retailers, and agents who help move goods from producers to consumers.When a manufacturer sells directly to consumers, these intermediaries are not needed.Thus, the channel becomes producer to consumer, eliminating the middlemen entirely.Wholesalers and retailers are both types of middlemen, so the correct option covers them all.Answer:C. middlemen