Explanation:

To determine the number of Mondays in a month, we need to find out how many days are there between the 1st and the 25th of that month.

Step 1: Determine the number of days from the 1st to the 25th of August.
To find the number of days between two dates, we subtract the day of the earlier date from the day of the later date and add 1. In this case, we subtract 1 from 25 and add 1 because both the 1st and 25th of August are included. So, the number of days from the 1st to the 25th of August is 25 - 1 + 1 = 25.

Step 2: Determine the day of the week on the 1st of August.
Since we know that the 25th of August is Thursday, we can determine the day of the week on the 1st of August by counting the number of days from Thursday to Sunday (since there are 7 days in a week).

- Thursday to Friday: 1 day
- Friday to Saturday: 1 day
- Saturday to Sunday: 1 day

So, the day of the week on the 1st of August is Sunday.

Step 3: Determine the number of complete weeks between the 1st and the 25th of August.
To determine the number of complete weeks, we divide the number of days from step 1 by 7. In this case, 25 divided by 7 equals 3 with a remainder of 4. Therefore, there are 3 complete weeks.

Step 4: Determine the day of the week on the 25th of August.
Since we know that there are 3 complete weeks, we can calculate the day of the week on the 25th of August by counting 3 days from Sunday.

- Sunday to Monday: 1 day
- Monday to Tuesday: 1 day
- Tuesday to Wednesday: 1 day

So, the day of the week on the 25th of August is Wednesday.

Step 5: Determine the number of Mondays in the month.
From the 1st to the 25th of August, we have 3 complete weeks and 4 additional days. Since the day of the week on the 25th of August is Wednesday, the additional days are Wednesday, Thursday, Friday, and Saturday. Out of these additional days, only one day is Monday. Therefore, the number of Mondays in August is 1.

Therefore, the correct answer is option B) 5.