Answer: Your question is incomplete, as your have omited the instruction to the question. Please let me assume this to be your question;
Consider the following sets of research questions and decide which one is the best research question (neither too broad nor too narrow).
A: What impact has deregulation had on the airline industry?
B: What percentage of commercial airline crashes was traced to negligent maintenance during the 10 years immediately preceding and following deregulation?
C: What impact has deregulation had on commercial airline safety?
ANSWER: Option C is the best research question. Which is "what impact has deregulation had on commercial airline safety?
Explanation: Option C is the best research question, because it is neither too broad not too narrow, it will lead the research to one direction, which is the impact deregulation has had on commercial airline, even though it may glance through other directions. Option C has a major point to research, which will narrow the research, to go into details on the impact of deregulation on safety.
Option A is too broad, and will make the research work to be too much. It is broad because the impact of deregulation on airline industry are very much, such as safety, compliance with government policy, flight ticket, flight fee at the hour of purchase, with many other. To research all of it in details will make the research boundaries to be large.
Option B is too narrow because, just one value and little explanation may end the research, which will not be enough to make up a research work.
In conclusion, Option C is the best among A and B, because you can add the percentage seen in airline crash in to the research work of option C, and you can also glance as many as other impact deregulation has on airline, while explaining the research work of option C.