The answer is D. The program prints:
woof

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