Answer:
Option D
Explanation:
According to Sangeeta, the father's birthday falls on one of the days among 9th, 10th, 11th and 12th December.
According to Natasha, the father's birthday falls on one of the days among 10th, 11th, 12th and 13th December.
Then, days common to both the groups are 10th, 11th and 12th December. So, the father's birthday falls on anyone of these days.