Answer: Python Puzzler #1267

The answer is D. The program prints:

[3, 14, 17, 21, 39, 42]

Checked by running the program for real.

sort() puts the list in order, smallest first. It changes the list itself.

scores = [21, 3, 42, 17, 14, 39]
scores.sort()
print(scores)

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