If the exchange rate between U$.$S$.$ dollars and Swiss francs changed from $0\mathrm{.}98$ francs per dollar to $0\mathrm{.}92$ francs per dollar, and financial inflows into the United States also changed, what factor might have caused this?

an increase in Swiss political risk

an increase in U$.$S$.$ business profitability

lower interest rates in Switzerland

$$ lower interest rates on U$.$S$.$ Treasuries