The chapter demonstrated that a firm borrowing in a foreign currency could potentially end up paying a very different effective rate of interest than what it expected. Using the same baseline values of a debt principal of SF$1\mathrm{.}3$million$,$ a$$ one$-$year period, an initial spot rate of SF$1\mathrm{.}5000/$$$,$ a $4\mathrm{.}705\%$ cost of$$ debt, and a $38\%$ tax$$ rate, what is the effective$$ after$-$tax cost of debt for one year for a U$.$S$.$ dollar$-$based company if the exchange rate at the end of the period$$ was:

a$.$ SF$1\mathrm{.}5000/$$

b$.$ SF$1\mathrm{.}4300/$$

c$.$ SF$1\mathrm{.}3980/$$

d$.$ SF$1\mathrm{.}6350/$$