$\frac{1}{3} + \frac{2}{9} + \frac{1}{10}$

LCD $= 90$:

$\frac{30}{90} + \frac{20}{90} + \frac{9}{90} = \frac{30 + 20 + 9}{90}$

This matches choice B: $\frac{30 + 20 + 9}{90}$.