The correct option is B 50 units
Ratio of the length of the sides of the triangle is 2:3:4.
So, the measure of the sides can be taken as 2x,3x, and 4x.
Perimeter =225 units
So, 2x+3x+4x=225
⇒9x=225
Dividing by 9 on both sides, we get:
⇒9x9=2259
⇒x=25
Hence, the length of the smallest side =2x=2×25=50 units