(Seeking) (to develop) a style (for which) she could express her own feelings, George O Keeffe created (a series of) abstract charcoal drawings. No Error
(for which) is the problem. To do something FOR the style would mean she is giving the style a present, or doing the style a favor – and none of that makes sense.
A more likely phrase would be (through which) or even (for expressing), but there is no rule that says you must come up with a quick fix in order to see that something is wrong.
Thanks, much appreciated
It could also just be simply “with which”
Yeah, I’d go with “with which” because recasting the sentence as “a style she could express her own feelings with” makes perfect sense and meets collocation/preposition conventions.