The answer is D. The program prints:
CC AA TT
Why?
A for loop can go through a string one letter at a time. Each letter is printed 2 times in a row.
Trace table
A trace table follows the program step by step. Here’s this one:
| letter | printed |
|---|---|
| C | CC |
| A | AA |
| T | TT |
The code again
for letter in "CAT":
print(letter * 2)Try it: change one number in the program and predict the new output before you run it.