If H0 is in reality false and it is legitimate to use a directional H1, which of the following will yield a more powerful test?

If H0 is in reality false and it is legitimate to use a directional H1, which of the following will yield a more powerful test? 1. one-tailed alternative hypothesis 2. one-tailed or two-tailed alternative hypothesis will yield the same power 3. two-tailed alternative hypothesis 4. type of alternative hypothesis has no effect on power