Answer: Python Puzzler #3405

The answer is C. The program prints:

59

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
6	yes	6
59	yes	59
24	no	59
25	no	59
18	no	59

The code again

numbers = [6, 59, 24, 25, 18]
biggest = 0
for n in numbers:
    if n > biggest:
        biggest = n
print(biggest)