I think knowledge is a solid elementary while the choice is more essential. If one always encouter lots of good chance without enough power,and then he also fails undoubtedly. On the contray, I always believe the CHOICE is the way to lead you a successful direction, as well as without making a right choice,even you are nothing though you spare your effect on some fields.
I think that the knowledge is necessary
there is a saying: chance is for one who is ready.
if you have not enough knowleage,envn(even) if the chance is speciall for you,I think what you gain is nothing.