implied 'can't', can or can't be trained

well other than whether or if;there is no other option which is correct...so A is correct

GMAT doesn't require 'weather' to have second part necessarily.
This trend can be seen in other questions of OG as well.
And remeber it always prefers 'weather' over 'if' when it comes to chosing between 2 options, although sentence many not have the second option written explicitly.

One more example of similar use of 'weather' is:

Critics of the trend toward privately operated prisons consider corrections facilities to be an integral part of
the criminal justice system and question if profits should be made from incarceration.
(A) to be an integral part of the criminal justice system and question if
(B) as an integral part of the criminal justice system and they question if
(C) as being an integral part of the criminal justice system and question whether
(D) an integral part of the criminal justice system and question weather
(E) are an integral part of the criminal justice system, and they question whether

Here the right answer is D.

hey...the example u have mentioned has the idiomatic error as consider dont need to be followed by preposition so D is rgt..nothin to do with whether or if

i didnt say it is right only because it uses 'weather' and not 'if'.. offcourse it doesnt has idiomatic flaws as other sentences have.
but it is right answer and has 'weather' used in it without explicitly mentioning the second option of the condition.
so i wanted to say that at many places they have accredited a sentence to be right although it has only one option of condition menioned.

Alrgt got ur point