Which statement describes a strong U.S. dollar?

Which statement describes a strong U.S. dollar?

a. The exchange rate between the U.S. dollar and the yen changes from 1:95 to 1:102.
b. The exchange rate between the U.S. dollar and the euro changes from 1:95 to 1:92.
c. The exchange rate between the U.S. dollar and the euro remains 1:95.