"1" is right answer because if you find a modulo division with positive number with negative number then it always return a positive number as modulo division....
in your question ,a%b that means 3%(-8) it returns 3 however you try yourself by changing positive number it always give you same positive number( in the case of only single digit like 1,2,3,4...9) as remainder.
then ,after getting 3 as a remainder you have to divide it by 2,(3/2) it result as integer division and finally give 1 as output....