$5.$ For this question, please pick any two currencies in the world other than the US Dollars. For each currency, look up its exchange rate against the US Dollars today $($write them as units of local currencies per $1$ US Dollar$),$ and the exchange rate from a year ago. Please also specify the dates you retrieve the data.

a$.$ Report the exchange rates for both currencies. Compared with a year ago, which currency has depreciated against the US Dollar? Which currency has appreciated against the US Dollar?

b$.$ Suppose a Big Mac costs $$6$ to buy in the US$.$ Conver the price of a US Big Mac in the respective currencies you$$ve chosen using the spot exchange rate today.

c$.$ Based on the spot exchange rates today, calculate the cross rate between the currencies you$$ve chosen.

d$.$ Suppose the actual exchange rate between the currencies you$$ve chosen is different from the cross rate from part $($c$).$ Write down a hypothetical situation where you can earn a riskless profit from arbitraging between the currencies.