3) Massimo wants to save on calendars. So with his computer, he printed many sheets with the numbers of the days and next to each number the day of the week. Every month, Massimo chooses the appropriate sheet and places a removable label with the name of the month on top. How many sheets must he have printed at a minimum, if he wants the calendar to be usable for the entire third millennium?
(A) 12
$\begin{array}{ll}\text { (B) } 24 & \text { (C) } 28\end{array}$
(D) 30
(E) 32.
3) The answer is (C). There are four different types of months: with 28, 29, 30, or 31 days. A month of any type can start on any of the seven days of the week. Therefore, there can only be seven pages for each type of month. That is, $4 \times 7=28$ pages.