The current quotation of the euro against the U.S. dollar in the New York market is 1.2985-1.2988. That is to say, investor A needs to spend 1.2988 to buy a euro, and can get 1.2985 to sell a euro (first of all, he must understand the quotation "Bid/ask price" is relative to the bank's buying/selling price. For investors, it is the selling price/buying price)

If A buys a euro in the New York market, it costs 1.2988. If it can be sold in the European market at a price higher than 1.2988, then the arbitrage is successful. Obviously, item D is 1.2989 (for investors to sell things, look at the left side of all options)

Similarly, if A is If you sell one euro in the New York market, you will get 1.2985 US dollars. If you buy one euro in the European market at a price lower than 1.2985, the arbitrage will be successful. Look at the right side of all the options, option C is OK.

The difficulty lies in understanding the difference between buying and selling prices. I would like to comment on the deficiencies.