X was born on March 6, 2014. The same year Independence Day was celebrated on Friday. On which day X was born?

Number of days between 6th March 2014 and 15th August 2014 = 25 (remaining days of March) + 30 (number of days in April) + 31 (number of days in May) + 30(number of days in June) + 31(number of days in July)  + 15 (number of days in August = 162

Now, 162 when divided by 7, remainder is 1

So, if 15th August 2014 was Friday then 6th March 2014 must be 1 day before Friday which is Thursday.

So, option C is the correct answer.