Given, Original rent = Rs.5000
He had to pay rent within the first 10 days of the month otherwise he had to pay fine of Rs. 10 per day.
In January he paid Rs.5070
That is 5000+70
Original rent+ fine
5000+7*10
Therefore he pays a fine for 7 days
Therefore the date he pays the rent is January 17.
Option(c) is correct.