The answer is D: to concentrate on your personal areas of interest.
The most importante reason for setting a purpose before reading or even before doing a research is to <em>eliminate distraction</em>, which can be a <em>hindrance</em> for any desired development.<em> Having a purpose is to have an intention, a goal, which will be achieved only with </em><em>concentration</em><em> on one's personal areas of interest.</em>
<span>a. to provide a focus and thus avoid being overwhelmed if you do not set a path for yourself you may get sidetracked to prevent that you set a focus </span>
