Critical Reasoning

A vendor at a farmers' market wishes to increase sales of her organic radicchio. A 5-for-the-price-of-4 sale was successful in increasing sales of her organic peach marmalade, so the vendor decides to offer the same deal on the radicchio.

Which of the following is an assumption on which her plan depends?

(A) Consumers enjoy radicchio as much as they enjoy peach marmalade
(B) Consumers who are willing to purchase large quantities of marmalade, which has a shelf life of one year, will be similarly willing to purchase large quantities of radicchio, which has a shelf life of 5-10 days.
(C) Radicchio is currently in season.
(D) Due to the secret recipe used for the vendor's peach marmalade, the vendor has fewer competitors selling a comparable peach marmalade at the farmers' market than selling radicchio.
(E) The profit from selling 5 bunches of radicchio for the price of 4 will be greater than the profit from selling 5 jars of peach marmalade for the price of 4.
OA is b

why is option B and C rule out here as one of the correct answer? can anyone help me out here?

The conclusion: Selling radicchio 5 for 4 is a good idea.

The evidence: Selling marmalade at that discount was a good idea.

The assumption: There are no significant differences between sales of the two items. This is what Choice B says. If this were not true, if people who were willing to buy lots of marmalade were NOT willing to purchase large quantities of radicchio, the conclusion would be weakened. Therefore, this choice needs to be assumed for the conclusion to hold.

You asked about Choice C. This does not need to be assumed. If Radicchio is not currently in season, it still might be a good idea to sell it 5 for 4. There might not be as much of it, but who's to say that it still won't be profitably sold at that discount? Anyway, it might be in season in a few weeks.

I'm available if you'd like any follow up.