Answer: Python Puzzler #1310

The answer is A. The program prints:

[4, 12, 17, 21, 28, 29]

Checked by running the program for real.

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

scores = [29, 12, 28, 4, 17, 21]
scores.sort()
print(scores)

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