The answer is C. The program prints:
54

Why?
The loop remembers the biggest number it has seen so far, and replaces it whenever it finds a bigger one. This is how computers find the maximum.
Trace table
A trace table follows the program step by step. Here’s this one:
| n | n > biggest? | biggest |
|---|---|---|
| 25 | yes | 25 |
| 54 | yes | 54 |
| 19 | no | 54 |
| 39 | no | 54 |
| 11 | no | 54 |
The code again
numbers = [25, 54, 19, 39, 11]
biggest = 0
for n in numbers:
if n > biggest:
biggest = n
print(biggest)
Try it: change one number in the program and predict the new output before you run it.