Answer:D. 20
Step-by-step explanation:To answer this question, we will use the distance formula which is as follows:
distance =

We are given:
point (-9,7) representing (x1,y1)
point (9,-2) representing (x2,y2)
Substitute with the givens in the above formula to get the distance as follows:
distance =

= 9√5 which is approximately 20 units
Hope this helps :)