Answer:
Distance between two points (x1, y1) and (x2, y2):
D = sqrt((x1 - x2)^2 + (y1 - y2)^2)
Then, distance between two points (5, 9) and (-7, -7):
D = sqrt((5 + 7)^2 + (9 + 7)^2) = sqrt(144 + 256) = sqrt(400) = 20
=> Option A is correct
Hope this helps!
:)