Answer: A. foolishness of people.
The author is describing the behaviour of the people. He tells us that the multitude of about two or three hundred people were pushing each other, elbowing and jostling, in order to get closer to the cylinder. These people are acting foolishly. Not only are they being rude and inconsiderate, but they are trying to get closer to an unknown object that could be very dangerous. This passage, therefore, states how foolish people can be.