Blockchain could help to avoid double spending in cryptocurrency. Based on the information below, User A is sending 5 BTC to Users B and C almost simultaneously. Who is guaranteed to receive the payment from A? What rule describes the confirmation process of the transaction?

(3 Marks)

d. Bitcoin follows a gold mining process. Every 10 minutes, there will be a new block mined. Reward for each block mined is cut in half every four years. For the first 4 years (or first 4-year period), the reward for mining a new block is 50 bitcoins. How many bitcoins have been awarded in total over the second and the third 4-year periods (i.e. from end of the 4^th year to the end of the 12^th year)? Please show full workings in the space below.

(5 Marks)

For calculations please round your final answer to two decimal places, round any intermediary calculations to four decimal places.