Each of three charities in Novel Grove Estates has 8 persons serving on its board of directors. If exactly 4 persons serve on 3 boards each and each pair of charities has 5 persons in common on their boards of directors, then how many distinct persons serve on one or more boards of directors?  Select the correct option:
A) 8 B) 13 C) 16 D) 24 E) 27
A intersect B intersect C = 4   A intersect B but not C = 1   B intersect C but not A = 1   C intersec A but not B = 1   A only is 2; B only is 2; C only is 2   Therefore, total 13 members serve on one or more boards of directors.   ANSWER:13
<result>B</result>
Each of three charities in Novel Grove Estates has 8 persons serving on its board of directors. If exactly 4 persons serve on 3 boards each and each pair of charities has 5 persons in common on their boards of directors, then how many distinct persons serve on one or more boards of directors?