Inorganic pesticides remain active on the surfaces of fruits and vegetables for several days after spraying, while organic pesticides dissipate within a few hours after application, leaving the surface of the sprayed produce free of pesticide residue. Therefore, when purchasing from a farm that uses inorganic pesticides, one must be careful to wash the produce thoroughly before eating it to prevent the ingestion of toxins. But one need not worry about ingesting pesticides when purchasing from farms that use only organic pesticides.

The argument above assumes that
A) Consumers are aware of the origins of the produce they purchase.
B) Produce from farms that use organic pesticides reaches the consumer within hours after it is picked or harvested.
C) No farm uses both organic and inorganic pesticides.
D) No pesticide is capable of penetrating the skin of a fruit or vegetable.
E) The use of either type of pesticide does not increase the cost of produce.

Answer along with an explanation please.
[spoiler]
I chose C because the conclusion - "Therefore, when purchasing from a farm that uses inorganic pesticides, one must be careful to wash the produce thoroughly before eating it to prevent the ingestion of toxins. But one need not worry about ingesting pesticides when purchasing from farms that use only organic pesticides." is about using organic or inorganic pesticides.[/spoiler]