On July 15, 2022, a speculator took a short position on 4 contracts of Bitcoin futures traded on CME when the futures price was $21,000 for August 2022 delivery. Each CME Bitcoin futures contract is based on 5 Bitcoins. The initial and maintenance margins are $28,000 and $15,000 per contract, respectively. On July 20, 2022, the August 2022 Bitcoin futures price jumped to $24,000. (a) Compute the unrealized gain or loss for the speculator on July 20, 2022. (b) Determine if she will get a margin call on July 20, 2022, and if so, how much cash will she need to transfer immediately to her futures account