What was king referring to when he said, “the long night of their captivity” in paragraph one

Which is the best paraphrase of the text? the capability of a bicycle makes some people want to go very fast and others to go very slow. as long as you are careful, feel free to ride like the wind. when feeling brave on a bicycle you should ride fast, but when feeling afraid riding slow is wise. if you are unable to coast, it is pointless to even ride. if you’re going to ride a bicycle, you should throw caution to the wind and take over the road, swerving where you like and taking full advantage of your ride. it’s a real joy to be able to ride a bicycle, where you have the choice of going as fast or as slow as you like, using as much courage as you feel like using.