Based on the excerpt, the statement that best strengthens Feldman´s claim that people are mostly honest is b. Feldman´s payment system was largely successful. His payment system is based on honesty, because he leaves the bagels and a cash basket in which anyone who took a bagel would leave cash, even if people could take a bagel and not pay, or even take money out of the basket, that did not happen. As he says "it was an honor-system commerce scheme, and it worked."
B.) confident
It makes the most sense
When a person pays their debts, one can determine that the person is responsible and able. They become more trustworthy and reliable.