Which is the best version of the underlined portion of sentence 7 (reproduced below)?
While educating himself opened a lot of doors for Frederick Douglass, in his future as a free man, he wrote about how it made his life as a slave even harder.
a lot of doors for Frederick Douglass in his future
This is correct because the original sentence includes an unnecessary comma, which needs to be removed. The phrase “for Frederick Douglass in his future life as a free man” should not be broken up by any punctuation.