B,
glimpse means that you look at someone/something in a very short period of time. maybe it only lasts for a second.
Before the economic boom we know as the Great Depression, times were very different, especially in New York City. People were making money on Wall Street and Spending it lavishly- there was so much money going around it was barely calculable. However, New York was the home of the stock market, too. When it crashed, things went very downhill from there.
A. The description would not be needed because the audience can see the actor.
Context clues help define a difficult or unusual word. The clue may appear within the same sentence as the word to which it refers, or it may follow in a preceding sentence.