None will get you the exact same gear ratio.
140T main / 10T pinion = 14:1 gear ratio
150T main / 9T pinion = 16.6:1
150T main / 10T pinion = 15:1
150T main / 11T pinion = 13.6:1
So you see, you can either get a little under or a little more over, but you cant get it exactly the same.
The 11T pinion will be the closest to the ratio you had.
Hope that helps.