The correct option is C Saturday
On 31st December, 2005 it was Saturday.
Number of odd days from the year 2006 to the year 2009 = (1 + 1 + 2 + 1) = 5 days.
Therefore, On 31st December 2009, it was Thursday.
Thus, on 1st Jan, 2010 it is Friday and hence, 2nd Jan, 2010 is Saturday.