GMAT Sentence Correction (SC) | Re: In the mid-1920’s the Clyde Fan Factory of the Bosch Manufacturing Com

although i didn't understand well, thanks for your suggestions.

I have another question- You said in option E "would have is hypothetical", I think understanding such differences requires more practice, but is there any indication though which an inept student like can understand the differences. And one more thing, In B) does "investigating" modify the company? if so how to understand such usage?
Thanks isn't enough.