请教二级NOTES 2第77页的第9题

zmmengxue

请教二级NOTES 2第77页的第9题，对NOTES上给的答案解释不是很懂啊

原题：Assuming no transaction costs, if a U.S. investor can make risk-free profits by borrowing the Japanese yen,then,

A. the hedged Japanese interest rate is low relative to the U.S. interet rate.

B.the hedged Japanese interest rate is high relative to the U.S. interet rate.

C.the interest rate differential is approximately equal to the forward premium.

NOTE 上的答案是A。请教各位高人应该怎么去做这个题目？