Which of the following employs the nomothetic model of explanation?

Which of the following employs the nomothetic model of explanation?
 
  a. An examination of all the considerations that resulted in 85 of the senior class members being hired for the jobs of their choice.
 b. An attempt to understand all the reasons concerning why five former presidents of the United States ran for office.
 c. An isolation of the three most important reasons as to why men were selected to all the leadership positions at a former women's college that went coed.
 d. Listing the reasons given by first-year students for selecting the college they currently attend.
 e. All of these choices employ the nomothetic model of explanation.