OG 11-23,28(help!)

23 Of all the possible disasters that threaten American argriculture, the possibilty of an adverse change in climate is maybe the more difficult for anaylysis.

A maybe the more difficult for anaylysis

B is prabably the most difficult to analyze

C is maybe the most difficult for analysis

D is prabably the more difficult to analyze

E is, it may be, the analysis that is most difficult

the answer provided by OG is B, i could understand. OG's explanation is that  "maybe" should be replaced by "prabably", who could tell me why??

28 Beyond the immediate cash flow crisis that the museum faces, its survival depends on if it can broaden its membership and leave its cramped quarters for a site where it can store and exhibit its more than 12,000 artifacts.

A if it can broaden its membership and leave

B whether it can broaden its membership and leave

C whether or not it has the capability to broaden its membership and can leave

D its ability for broadening its membership and leaving

E the ability for it to broaden its membership and leave

the solution provided by OG is B, who could tell me why A is not the solution?

and why "depends on" must be followed by "whether", not "if"?

23 用词倾向性:标准书面语中,倾向于用情态动词或probably表示可能,而不倾向于使用maybe或perhaps 三者倾向性probably>perhaps>maybe

25 标准书面语中表示是否只能用whether,不能用if