Answer: Python Puzzler #3781

The answer is C. The program prints:

squeak

This answer was checked by running the program for real.

Why?

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

Trace table

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

keyvalue
duckquack
frogribbit
mousesqueak
owlhoot

The code again

sounds = {
    "duck": "quack",
    "frog": "ribbit",
    "mouse": "squeak",
    "owl": "hoot",
}
print(sounds["mouse"])

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