Respuesta :
We can answer to this question by singling out incorrect options. It is obvious that the excerpt is about the development of bicycle or first bicycles. Therefore, there is no competition, yet. We don't have any information about a successful trial or patent after that. The excerpt describes the development of sufficiently working, a useful bicycle. Of course, the developers would have considered safety features, but we don't observe it in this excerpt. The correct answer is the first option - the gradual improvements in bicycle design.