The egyptians devised a calendar of twelve months, with each month containing days. a. twenty b. ten c. thirty

The correct answer is - C. Thirty.

The Egyptian calendar was a solar calendar. It had 365 days in a year, but it was slightly differently arranged than the modern calendars. The calendar had 3 seasons, each season had 4 months, and since every month had 30 days, each season had 120 days. So, 3 seasons, all with 120 days, gave 360 days. The additional 5 days, the Egyptians added in a separate interstellar 5 day long month which was consider as out of the year proper. It was not perfect, but it served them well.