Answer:
C) (w/r) falls in A and rises in B
Step-by-step explanation:
Since country A has abundant capital, but lacks labor, the price of labor will originally be very high, but since the country is trading with country B, then the price of labor will decrease. On the other hand, in country B there exists an abundance of labor, so the price of labor was originally very low. As they engage in trade with country A, the price of labor will increase.