The answer is D. The program prints:
[6, 9, 12, 15, 18]
This answer was checked by running the program for real.
Why?
range(6, 20, 3) counts from 6 in steps of 3 and stops before 20.
The code again
print(list(range(6, 20, 3)))
Try it: change one number in the program and predict the new output before you run it.