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? ['employed people whose strict religious observances require that they refrain from working every seventh day', 'people who have birthdays or other anniversaries on December 30 or 31', 'people who have to plan events several years before those events occur', 'employed people who have three-day breaks from work when holidays are celebrated on Mondays or Fridays']