A reaction between ethene and oxygen is used to produce epoxyethane. When silver is combined with ethene, the reaction for producing epoxyethane occurs much faster. What role does silver play in this chemical process?
A. Silver is a catalyst in this reaction.
B. Silver is a p-type semiconductor in this reaction.
C. Silver causes hydrolysis in this reaction.
D. Silver is an n-type semiconductor in this reaction.