LET us CALCULATE what day was on 1st December 2017.2000 years = 0 ODD days.From 2001 to 2016, the number of odd days is 1 + 1 + 1 + 2 + 1 + 1 + 1 + 2 + 1 + 1 + 1 + 2 + 1 + 1 + 1 + 2 = 20 or 6 odd days.From January to December, the number of odd days is 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 1( 1st day of December) = 335 or just 6 odd days.Total odd days is 12 or 5 which is Friday.1st December is Friday, So 6th December will be first WEDNESDAY of December 2017.6, 13, 20, 27 are Wednesdays in December 2017.Hence, 13 is the correct answer.