The excerpt this question refers to can be found online. Since it is too long, I will not add it here. It belongs to the book "Freakonomics," by Levitt and Dubner.
Answer:
The conclusion concerning mood and honesty is best supported by the statement that follows:
B. Stressful fall and winter holidays generally cause payment rates to drop.
Step-by-step explanation:
In the excerpt, we are told about a man who leaves a basket with bagels at different companies for employees to buy. He does not stay there to sell the bagels; he simply trusts people's honesty when it comes to money.
It turns out that people pay higher rates when they are in a good mood. However, after stressful holidays or when the weather is not that good, people tend to pay lower rates, and even the number of bagels stolen (not paid for) increases. In other words, mood and honesty are connected.