In order to add the fractions, we need to create complex fractions with a Least Common Denominator (LCD).
The LCD between 9 and 2 is 18
3 1/2 = 3(18/18) + 9/18 = 54/18 + 9/18 = 63/18
3/9 = 6/18
So now we can solve...
3 1/2 + 3/9 is the same as 63/18 + 6/18 = 69/18 = 3 5/6 which is none of the given answers.