Answer: Python Puzzler #1685

The answer is A. The program prints:

quack

Checked by running the program for real.

A dictionary stores pairs: a key and its value. sounds["duck"] looks up the key ‘duck’ and gives back its value.

A trace table follows the program step by step. Here’s this one:

sounds = {
    "sheep": "baa",
    "cow": "moo",
    "lion": "roar",
    "duck": "quack",
}
print(sounds["duck"])

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