If All Else Is Held Constant,what Would Happen to the Equilibrium

Multiple Choice

If all else is held constant,what would happen to the equilibrium price and quantity of iPhones if the price of an Android phone decreased?

A) They would both increase.
B) They would both decrease.
C) One would increase and one would decrease,but we don't know which would do what.
D) The price would increase and the quantity would decrease.
E) The price would decrease and the quantity would increase.