Based on the passage, the expression "knowledge systems" ( last sentence of the passage ) most likely refers to which...

Could someone confirm or deny if my reasoning for the following answer choices is either right or wrong? Answer Choice "A" - Sets of Farming Techniques developed by crop genetics researchers. [Seems to me that the paragraph doesn't describe crop genetic researchers at all hence this is why I didn't choose.] Any comments as to that? Answer Choice "B" - The passing of heirloom seed stock from generation to generation. [Generations aren't spoken about in the paragraph or anywhere in the preceding lines from the line cited. Hence this is why I didn't choose.] Answer Choice "C" - Techniques of hybridization brought to North America from elsewhere. [Again, the paragraph doesn't talk about techniques brought from elsewhere in my estimation.] Answer Choice "E" - Fail safe techniques for successful farming operations. [The language just seems too strong with 'fail safe techniques'. That's not ever really alluded to in the paragraph. Can someone give me their take on why the answer choices are wrong and the correct one is right? I'd appreciate it a lot.