Which of the following is an example of triangular arbitrage initiation? a. buying a currency at one bank's ask and selling at another bank's bid, which is higher than the former bank's ask. b. buying Singapore dollars from a bank (quoted at $.55) that has quoted the South African rand (SAR)/Singapore dollar (S$) exchange rate at SAR2.50 when the spot rate for the rand is $.20. c. buying Singapore dollars from a bank (quoted at $.55) that has quoted the South African rand/Singapore dollar exchange rate at SAR3.00 when the spot rate for the rand is $.20. d. converting funds to a foreign currency and investing the funds overseas.

---Can you please show me step by step how the answer C produced an arbitrage, what was the calculation??---