The answer is C. The program prints:
moo

Why?
A dictionary stores pairs: a key and its value. sounds["cow"] looks up the key ‘cow’ and gives back its value.
Trace table
A trace table follows the program step by step. Here’s this one:
| key | value |
|---|---|
| bee | buzz |
| cat | meow |
| cow | moo |
| mouse | squeak |
The code again
sounds = {
"bee": "buzz",
"cat": "meow",
"cow": "moo",
"mouse": "squeak",
}
print(sounds["cow"])
Try it: change one number in the program and predict the new output before you run it.