Figure $15\mathrm{.}1$ shows the market for the Swiss franc. In the figure, the initial demand for marks and supply of marks are depicted by D$0$ and S$0$ respectively.

Figure $15\mathrm{.}1.$ The Market for the Swiss Franc$$A graph shows market for the Swiss Franc.

Refer to Figure $15\mathrm{.}1.$ Suppose that the United States increases its imports from Switzerland, resulting in a rise in the demand for francs from D$0$ to D$1.$ Other things equal, under a floating exchange rate system, the new equilibrium exchange rate would be

a$.$ $$0\mathrm{.}50$ per franc.

b$.$ $$0\mathrm{.}40$ per franc.

c$.$ $$0\mathrm{.}70$ per franc.

d$.$ $$0\mathrm{.}60$ per franc.