<p>Surely one of the most far-reaching changes in the nineteenth century will be the change from working at home to working in the factory.</p>
<p>I picked no error, however, the answer key says the answer is B (by the way, the link in the Consolidated Answers List shows a post where the OP posted the wrong correct answer).</p>
<p>Why is the answer B? The sentence doesn't grammatically specify any specific tense, even if it was in the nineteenth century and we don't live in the nineteenth century now, couldn't the sentence have been written in any period of time, and thus the tense may still refer to the future?</p>