LSAT Logical Reasoning Question of the Day

It appears that warm temperatures tend to improve both productivity and attitudes. Empirical evidence supports the general assumption that outdoor temperatures affect the way people feel and, perhaps as a result, the amount they get done. These conclusions are drawn from a recent study which found that when temperatures increase at the beginning of spring people are more likely to smile, make more money than in the winter, greet strangers, and report that they are content with their lives.

Which of the following is most supported by the study?