Final answer:
The independent variable is the number of cups of lemonade Wendy sells (c), and the dependent variable is the amount of money she earns (m), so the answer is A) c is the independent variable and m is the dependent variable.
Step-by-step explanation:
In the context of the question where Wendy is selling lemonade, the number of cups of lemonade she sells is the independent variable and the amount of money she earns is the dependent variable. This is because the money earned from selling lemonade depends on how many cups are sold. The more cups Wendy sells, the more money she will earn. Hence, the correct answer is A) c is the independent variable and m is the dependent variable.