Correct Answer - Option 2 : Thursday
5th Monday of April is possible only on two dates : 29th April or 30th April
Case 1 : 29th April Monday
No. of days from 30th April to 1st November = ( 1 + 31 + 30 + 31 + 31 + 30 + 31 + 1 ) = 186 Days
No. of odd days = 186
÷ 7 = 26 weeks and 4 odd days
1 November = Friday
29th November and 30th November are Friday and Saturday respectively.
So, in this case 5th Thursday is not possible.
Case 2 : 30th April Monday
No. of days from 1st May to 1st November = ( 31 + 30 + 31 + 31 + 30 + 31 + 1 ) = 185 Days
No. of odd days = 185 ÷ 7 = 26 weeks and 3 odd days
So, 1st November will be Thursday.
Therefore, 29th November will be 5th Thursday. Birthday of second child is on 29th November.
Thursdays in December = 6th December, 13th December, 20th December, 27th December.
Hence, Thursday is the correct answer.