C) The description of those who come to Johannesburg shows that people viewed Johannesburg as a solution to every problem, conveying the desperation of the people while foreshadowing the idea that Johannesburg will be overwhelmed by the number of people coming to it.
The excerpt repeatedly holds the word "Johannesburg", to put the focus on it as a place where anyone can go to, and where anything can be done, especially if it is aimed to solve a problem (To pay taxes, to secretly deliver an unborn child, etc.). It certainly conveys the message that Johannesburg is seen as a solution to every problem, and therefore it leads the reader with a feeling that in the future it may be largely populated by people who want to solve their issues.