Answer:
A. 40 degrees
Step-by-step explanation:
The question is asking how many degrees can a nonagon be rotated so that it looks like it did originally. This is also how many degrees on triangle on a nonagon would be.
The nonagon has 9 congruent sides, so it can be split up into 9 congruent triangles. The inside angle can be found by dividing 360 by 9, which is equal to 40 degrees.