Answer: Python Puzzler #3673

The answer is C. The program prints:

58

This answer was checked by running the program for real.

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
1	yes	1
9	yes	9
39	yes	39
58	yes	58
57	no	58

The code again

numbers = [1, 9, 39, 58, 57]
biggest = 0
for n in numbers:
    if n > biggest:
        biggest = n
print(biggest)