Intertemporal arbitrage of foreign exchange futures refers to the trading behavior that traders buy or sell foreign exchange futures contracts of the same variety and different delivery months at the same time, hoping that the spread between contracts will develop in a favorable direction, and then close their positions and make profits. Intertemporal arbitrage of foreign exchange futures can be divided into bull spread, bear market arbitrage and butterfly arbitrage. The AC item is correct. Butterfly arbitrage of foreign exchange futures is an intertemporal arbitrage combination of a bull market spread and a bear market arbitrage within a * * * delivery month. Item d is correct. So the answer to this question is ACD.