Answer: Python Puzzler #980

The answer is B. The program prints:

[4, 7, 10, 13, 16, 19]

Checked by running the program for real.

range(4, 20, 3) counts from 4 in steps of 3 and stops before 20.

print(list(range(4, 20, 3)))

Try it: change one number in the program and predict the new output before you run it.