Answer: Python Puzzler #3435

The answer is D. The program prints:

42

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
41	yes	41
42	yes	42
26	no	42
40	no	42
25	no	42

The code again

numbers = [41, 42, 26, 40, 25]
biggest = 0
for n in numbers:
    if n > biggest:
        biggest = n
print(biggest)