Mark has a trading account in a crypto exchange and he has 1.25 bitcoins in his account. When Mark trades using his account, a fixed transaction fee of $2 is imposed if the transaction amount is less than $500. If the transaction is greater than $500, the fee will be 0.5% of the transaction amount. The number of bitcoins he trades is determined by the transaction amount less the transaction fee and the traded price of Bitcoin.

(a) Describe and assess what will happen in the blockchain when Mark carries out a buy/sell transaction.