In which of the following circumstances would a cartel be most likely to work?

(A) The coffee market, where the product is standardised and there are a large number of
coffee growers.
(B) The automobile industry, where there are few producers but there is great product
differentiation.
(C) The market for copper, where there are very few producers and the product is
standardised.
(D) The fast-food market, where there are a large number of producers but the demand for
fast food is inelastic.