Explanation:

The fire accident took place on Sunday (option B).

Reasoning:
To determine the day on which the fire accident took place, we need to consider certain factors.

1. Context:
The context of the question does not provide any specific information regarding the date or month of the fire accident. Therefore, we need to rely on general knowledge and logic to find the answer.

2. Days of the Week:
To determine the day of the week for a specific date, we can use the concept of the Gregorian calendar. However, it is important to note that the calendar repeats itself every 400 years, and the rules for determining the day of the week for a given date are based on this cycle.

3. Leap Year:
In the Gregorian calendar, a leap year occurs every four years. This means that February has 29 days instead of the usual 28 days.

Given that we do not have any information about the year, we can assume a regular year with 365 days.

4. Counting the Days:
To determine the day of the week, we can count the number of days from a known reference point. In this case, we can start counting from a known day and determine the day on which the fire accident took place.

Assuming that the known day is Monday, we can count the days as follows:
- Monday (1st day)
- Tuesday (2nd day)
- Wednesday (3rd day)
- Thursday (4th day)
- Friday (5th day)
- Saturday (6th day)
- Sunday (7th day)

Since the fire accident took place after six days, we can conclude that it happened on Sunday.

Therefore, the correct answer is option B) Sunday.