Question 5 - Back-running describes the process where an adversary attempts to execute its own transaction immediately after the victim's transaction executes. For example, given two exchange markets A and B, both trading ETH/USD at a price of 1000. If a victim's trade (with a gas price of 100GWei) is expected to push exchange A's price to 1100 ETH/USD, the adversary can attempt to back-run the victim to perform arbitrage between A and B. Which of the following method will have the highest back-running success rate?