Bella thinks that she can make amazing cold coffee by soaking coffee beans in the fridge overnight. She pours this cold brew into a cup.

She also buys a tall dark roast from Starbucks, just in case.

The independent variable in this experiment is because

Temperature of the fridge

Explanation:

The independent variable is the temperature of the fridge.

The hypothesis statement would be "if coffee beans are soaked overnight in a fridge then cold coffee is produce because of the temperature of the fridge".

An independent variable is the cause in an experimental design or set up. It is the variation on this variable that produces the effect we desire to study.

The dependent variable is the cold coffee. It is the cause of putting the coffee in the fridge of overnight.

it's c. (to reduce the greenhouse effect/carbon gasses)