If the International Fisher Effect (IFE) Did Not Hold Based

If the international Fisher effect (IFE) did not hold based on historical data, then this suggests that:

A) some corporations with excess cash can lock in a guaranteed higher return on future foreign short-term investments.
B) some corporations with excess cash could have generated profits on average from covered interest arbitrage.
C) some corporations with excess cash could have generated higher profits on average from foreign short-term investments than from domestic short-term investments.
D) most corporations that consistently invest in foreign short-term investments would have generated the same profits (on average) as from domestic short-term investments.