求教一道lsat题

It takes 365.25 days for the Earth to make one complete revolution around the sun. Long – standing convention makes a year 365 days long, with an extra day added every fourth year, and the year is divided into 52 seven-day weeks. But since 52 times 7 is only 364, anniversaries do not fall on the same day of the week each year. Many scheduling problems could be avoided if the last day of each year and an additional day every fourth year belonged to no week, so that January 1 would be a Sunday every year.

The proposal above, once put into effect, would be most likely to result in continued scheduling conflicts for which one of the following groups?

(A) people who have birthdays or other anniversaries on December 30 or 31

(B) employed people whose strict religious observances require that they refrain from working every seventh day

(C) school systems that require students to attend classes a specific number of days each year

(D) employed people who have three-day breaks from work when holidays are celebrated on Mondays or Fridays

(E) people who have to plan events several years before those events occur 20. Graphologists claim that it is possible to detect permanent character traits by exa

答案是B，我怎么也想不通，呈请指教