The correct option is (b) 5.
But, sin x can not be more than 1.
∴ sin x=1/3
It means, value of sin x is positive.
It means, x lies in first and second quadrant.
So, there are 2 values from 0 to 2π.
So, from 0 to 5π, there will be 5 values for x that will satisfy the given equation.