Which of the Following Would Not Cause the Market Supply

Which of the following would not cause the market supply of cell phones to change?

A) Telecommunications are deregulated,and anyone who wants to can produce and sell cell phones.
B) A cheaper technology for producing plastics used in producing cell phones is developed.
C) A reduction in the demand for cell phones causes the price to fall.
D) Taxes levied on cell phone production are reduceD.A change in the price of cell phones will cause a movement along the supply curve or a change in the quantity supplied.