Assume that the U.S. interest rate is 10%, while the British interest rate is 15%. If interest rate parity exists, then: 10% 15% O a. U.S. investors will earn a higher rate of return when using covered interest arbitrage than what they would earn in the U.S. Ob. U.S. investors will earn 15% whether they use covered interest arbitrage or invest in the U.S. 15% O c. U.S. investors will earn 10% whether they use covered interest arbitrage or invest in the U.S. 10% O d. British investors who invest in the United Kingdom will achieve the same return as U.S. investors who invest in the U.S