11. On the floor of a futures exchange one futures contact is traded in which the party going long is closing his existing position while the party going short is opening a new position. What are the impacts of this trade on the trading volume and the open interest on the exchange?

(a) Both the trading volume and the open interest increase by 1.

(b) Bothe the trading volume and the open interest stay unchanged.

(c) The trading volume increases by 1, while the open interest decreases by 1.

(d) The trading volume increases by 1, while the open interest stays unchanged.