Answer:
D. Narrow his focus
Explanation:
In writing a research,a topic has to be selected first. This could be provided by a supervisor or the individual, on a topic he is interested in. After forming a topic, many general questions should be formed. This would provide a wide view from which to assess the topic.
Too many general questions ought to be further narrowed into more specific questions. It is important that the researcher chose a topic on which information could be found easily. This would make it easier for the questions to be easily narrowed and not too broad. He should also avoid open ended questions, that is yes or no questions, so as to make the information more meaningful.
Out of the choices given, the concrete nouns are toolbox, lamb, iron, and tooth.
