Answer: Python Puzzler #1510

The answer is A. The program prints:

squeak

Checked by running the program for real.

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

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

sounds = {
    "dog": "woof",
    "lion": "roar",
    "mouse": "squeak",
    "sheep": "baa",
}
print(sounds["mouse"])

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