Answer:
Option C. Silver is a catalyst in this reaction.
Step-by-step explanation:
From the question given, we discovered that the addition of silver in the reaction between ethene and oxygen produces epoxyethane at a much faster rate. This simply means that silver act as a catalyst in this reaction.
A catalyst is substance that increases the rate of a reaction without itself taking part in the reaction. The catalyst creates an alternate path way by lowering the activation energy so that the reaction can proceed at a much faster rate.
Since the addition of silver makes reaction to occur at a much faster rate, it therefore means that silver act as a catalyst in the reaction.