However, it is really a bad question for two reasons. First, hektometers is a unit which is never used. Second, you can do the conversion without using any of those conversion factors, viz:
25L (10^-3 m^3 /L ) (1 hm^3/ 100^3 m^3) = (25)(10^-3)/(10^6) hm^3 = 25 * 10^-9 hm^3
so you could argue that any of the choices is a correct answer.