Let the no. of sales by Rama = x
Let the no. of sales by Bob = y
x + y = 190 and y = 190 - x
Target question => Raina made how many more sales than Bob?
x - y = ??
Statement 1: The difference between the number of sales Raina made and the number of sales Bob made was 10% of the number of sales Raina made.
x - y = 10% of x = 0.1x
From the question stem; y = 190 - x.
Hence, x - (190 - x) = 0.1x
2x - 190 = 0.1x
1.9x = 190
x = 190/1.9 = 100
From y = 190 - x = 190 - 100 = 90
So x - y = 100 - 90 = 10. Statement 1 is SUFFICIENT.

Statement 2: Bob made 9/19 of the total number of sales made by himself and Raina.
$$y=\frac{9}{19}of\ \left(x+y\right)\ from\ the\ question\ stem\ x+y=190$$
$$y=\frac{9}{19}\cdot190=9\left(10\right)=90$$
$$x+y=190;\ \ So\ x+90=190,\ then\ x=100$$
$$Therefore\ x-y=100-90=10$$
Hence, statement 2 is SUFFICIENT.

Since each statement alone is sufficient, the correct answer is option D.