Final answer:
The length of Alana's vacation (L) is the independent variable, and the number of shirts she packs (s) is the dependent variable because the number of shirts packed depends on the vacation's length.
Step-by-step explanation:
In the scenario described, there is a relationship between the length of Alana's vacation and the number of shirts she packs. To determine which variable is the independent variable and which is the dependent variable, we look at which variable is determined first without the influence of the other. In this case, the length of the vacation (L) would be decided first, making it the independent variable. Then, based on the length of the vacation, Alana decides how many shirts (s) to pack, which makes the number of shirts she packs the dependent variable. This is because the number of shirts depends on the trip's length.
Therefore, the correct answer is B. L is the independent variable and s is the dependent variable. In mathematical studies or experiments, the independent variable typically determines the dependent variable, as seen in the equation for change in length (ΔL), force (F), and other examples provided.