25. Don, a manager at Super Insurer, has just designed a major change in company policy. He has asked two employees of the company, Jack and Jill, to spread the news of the change to other employees. Based on centrality measures of the company’s email traffic, Don believes Jill will spread the news more rapidly and to more employees through email than Jack. This belief is based on Jill’s high measure in which one of the following centrality measures?