Concept:
A month has 5 of a specific weekday if that weekday falls within the first few days of the month, depending on the total number of days:
- In a month with 31 days, any weekday that falls on the 1st, 2nd, or 3rd of the month occurs 5 times.
- In a month with 30 days, any weekday that falls on the 1st or 2nd of the month occurs 5 times.
- In a month with 28 days, every weekday occurs exactly 4 times.
Calculation:
First, we determine the day of the week for January 1, 1915. Using the reference that January 1, 1900 was a Monday:
Number of years from 1900 to 1914 = 15 years.
Number of leap years in this period (1904, 1908, 1912) = 3.
Total odd days = 15 + 3 = 18 days.
18 ÷ 7 = 2 weeks and 4 odd days.
Day on January 1, 1915 = Monday + 4 days = Friday.
I. August 1915:
August has 31 days.
Odd days from January 1 to August 1, 1915 = Jan(3) + Feb(0) + Mar(3) + Apr(2) + May(3) + Jun(2) + Jul(3) = 16 days.
16 ÷ 7 = 2 weeks and 2 odd days.
Day on August 1, 1915 = Friday + 2 days = Sunday.
If August 1 is Sunday, then August 2 is Monday and August 3 is Tuesday.
Since the 3rd of August is a Tuesday and the month has 31 days, Tuesday occurs 5 times (on the 3rd, 10th, 17th, 24th, and 31st).
II. December 1915:
December has 31 days.
Odd days from August 1 to December 1, 1915 = Aug(3) + Sep(2) + Oct(3) + Nov(2) = 10 days.
10 ÷ 7 = 1 week and 3 odd days.
Day on December 1, 1915 = Sunday + 3 days = Wednesday.
The first three days of December are Wednesday (1st), Thursday (2nd), and Friday (3rd).
As Tuesday does not fall on the 1st, 2nd, or 3rd, there are only 4 Tuesdays in December 1915 (on the 7th, 14th, 21st, and 28th).
Therefore, only August 1915 had 5 Tuesdays.
Hence, the correct answer is Only I.