All but Which One of the Following Could Shift the Supply

All but which one of the following could shift the supply curve for bicycles?

A) An increase in the price of aluminum used in the bicycles.
B) An increase in the price of bicycles.
C) An increase in the number of bicycle manufacturers.
D) A new,cheaper way of producing bicycles.
E) A new union contract that raises the price of labor in bicycle factories.