We need to calculate the number of days from 5 September 2015 to 5 February 2016:
Days remaining in September 2015 = 30 − 5 = 25 days
Days in October 2015 = 31 days
Days in November 2015 = 30 days
Days in December 2015 = 31 days
Days in January 2016 = 31 days
Days in February 2016 = 5 days (up to the target date)
Total number of days = 25 + 31 + 30 + 31 + 31 + 5 = 153 days
To find the odd days, divide the total days by 7:
153 ÷ 7 = 21 weeks and 6 odd days (remainder)
Given that 5 September 2015 was Saturday.
The day on 5 February 2016 = Saturday + 6 odd days
Counting 6 days forward from Saturday: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday.
Hence, the day on 5 February 2016 was Friday.
Alternate Method
We can find the odd days for each month individually to simplify the addition:
September: 25 days ⇒ 25 ÷ 7 = 4 odd days
October: 31 days ⇒ 31 ÷ 7 = 3 odd days
November: 30 days ⇒ 30 ÷ 7 = 2 odd days
December: 31 days ⇒ 31 ÷ 7 = 3 odd days
January: 31 days ⇒ 31 ÷ 7 = 3 odd days
February: 5 days ⇒ 5 odd days
Total sum of odd days = 4 + 3 + 2 + 3 + 3 + 5 = 20 days
Final odd days = 20 ÷ 7 = 2 weeks and 6 odd days
The day was Saturday + 6 days = Friday.
Therefore, the correct answer is Friday.