Sentence Correction (SC) | Re: Discussion of greenhouse effects have usually had as a focus the

Let's compare (B) and(C).

(B) Discussion of greenhouse effects has usually had as its focus whether Earth would get warmer and what the extent would be,

(C) Discussion of greenhouse effects has usually focused on whether Earth would grow warmer and to whatextent,

Both are OK in terms of parallelism specifically.

The problem with (B) is that the meaning conveyed is not clear. In (B) we have[color=#0000ff] "whether
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