Angle C = 180-120 = 60°
Sum of measures of all interior angles of a Triangle = 180°
<A+<B+<C=10
2x+3x+60=180
5x+60=180
5x=180-60
5x=120
x=120/5
x=24°
Angle B = 3x = 3×24 = 72°
Option 3. 72