Which example best illustrates a leap of abstraction?

The option that best illustrates a leap of abstraction is the statement about needing chaperones for the bivouac and then making a generalization about all senior members being lazy. A leap of abstraction involves moving from a specific situation to a more generalized claim. In this case, the need for chaperones, which is a specific concern based on a particular event, leads to a broad and negative generalization about the entire group of senior members. This generalization does not consider the individual contributions or behaviors of the senior members but rather categorizes them all based on the speaker's frustration.

In contrast, the other options maintain a more concrete or specific focus. The statement about the weather is simply a suggestion based on a current condition, while the comments on team improvement and student study habits present broader trends or observations without making sweeping generalizations that imply a negative quality about a whole group. Therefore, the first statement captures the essence of a leap of abstraction effectively through its sweeping conclusion about senior members.