Under a Gold Standard in Which One Dollar Could Be

Under a gold standard in which one dollar could be turned in to the U.S. Treasury and exchanged for 1/20th of an ounce of gold and one Swiss Franc could be exchanged for 1/100th of an ounce of gold,an exchange rate of ________ francs to the dollar would stimulate a flow of gold from the United States to Switzerland.

A) 7
B) 6
C) 5
D) 4