Which is the dependent and indpendent variable?

Consider the following question: "Which phone is easier to use - the iPhone or an Android-based phone?" What is the dependent variable in this question?
Answer a. Ease of use
b. One of the two phones
c. The question of whether one phone is easier to use than the other
d. The iPhone and the Android-based phone

Added (1). So the independent variable is A or C?

The dependent variable is 'b' because you can change the phones out independently as much as you want, however the answer if which is easier is dependent upon which phone you use…