B : rotation.
Translation is if you are moving the shape from one place to the other. Reflection is if you are flipping the shape over a line ( which it is not ) and dilation is when the shape is becoming bigger or smaller.
Y=3x
explain
4x3=12 , 5x3=15 , 6x3=18 ,.......
Step-by-step explanation:

the polygon is 15 sided.